Merge bitcoin/bitcoin#22646: build: tighter Univalue integration, remove `--with-system-univalue`

0f95247246344510c9a51810c14c633abb382e95 Integrate univalue into our buildsystem (Cory Fields)
9b49ed656fb2b687fbbe8a3236d18285957eee16 Squashed 'src/univalue/' changes from 98fadc0909..a44caf65fe (fanquake)

Pull request description:

  This PR more tightly integrates building Univalue into our build system. This follows the same approach we use for [LevelDB](https://github.com/bitcoin-core/leveldb/), ([`Makefile.leveldb.include`](https://github.com/bitcoin/bitcoin/blob/master/src/Makefile.leveldb.include)), and [CRC32C](https://github.com/bitcoin-core/crc32c) ([`Makefile.crc32c.include`](https://github.com/bitcoin/bitcoin/blob/master/src/Makefile.crc32c.include)), and will be the same approach we use for [minisketch](https://github.com/sipa/minisketch); see #23114.

  This approach yields a number of benefits, including:
  * Faster configuration due to one less subconfigure being run during `./configure` i.e 22s with this PR vs 26s
  * Faster autoconf i.e 13s with this PR vs 17s
  * Improved caching
  * No more issues with compiler flags i.e https://github.com/bitcoin/bitcoin/pull/12467
  * More direct control means we can build exactly the objects we want

  There might be one argument against making this change, which is that builders should have the option to use "proper shared/system libraries". However, I think that falls down for a few reasons. The first being that we already don't support building with a number of system libraries (secp256k1, leveldb, crc32c); some for good reason. Univalue is really the odd one out at the moment.

  Note that the only fork of Core I'm aware of, that actively patches in support for using system libs, also explicitly marks them as ["DANGEROUS"](https://github.com/bitcoinknots/bitcoin/blob/a886811721ce66eb586871706b3f5dd27518ac3e/configure.ac#L1430) and ["NOT SUPPORTED"](https://github.com/bitcoinknots/bitcoin/blob/a886811721ce66eb586871706b3f5dd27518ac3e/configure.ac#L1312). So it would seem they exist more to satisfy a distro requirement, as opposed to something that anyone should, or would actually use in practice.

  PRs like #22412 highlight the "issue" with us operating with our own Univalue fork, where we actively fix bugs, and make improvements, when upstream (https://github.com/jgarzik/univalue) may not be taking those improvements, and by all accounts, is not currently actively maintained. Bitcoin Core should not be hamstrung into not being able to fix bugs in a library, and/or have to litter our source with "workarounds", i.e #22412, for bugs we've already fixed, based on the fact that an upstream project is not actively being maintained. Allowing builders to use system libs is really only exacerbating this problem, with little benefit to our project. Bitcoin Core is not quite like your average piece of distro packaged software.

  There is the potential for us to give the same treatment to libsecp256k1, however it seems doing that is currently less straightforward.

ACKs for top commit:
  dongcarl:
    ACK 0f95247246 less my comment above, always nice to have an include-able `sources.mk` which makes integration easier.
  theuni:
    ACK 0f95247246344510c9a51810c14c633abb382e95. Thanks fanquake for keeping this going.

Tree-SHA512: a7f2e41ee7cba06ae72388638e86b264eca1b9a8b81c15d1d7b45df960c88c3b91578b4ade020f8cc61d75cf8d16914575f9a78fa4cef9c12be63504ed804b99

19 files changed, 1400 insertions, 392 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 9d15120b72..68c81c1a12 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -6,7 +6,7 @@
 print-%: FORCE
 	@echo '$*'='$($*)'
 
-DIST_SUBDIRS = secp256k1 univalue
+DIST_SUBDIRS = secp256k1
 
 AM_LDFLAGS = $(LIBTOOL_LDFLAGS) $(HARDENED_LDFLAGS) $(GPROF_LDFLAGS) $(SANITIZER_LDFLAGS)
 AM_CXXFLAGS = $(DEBUG_CXXFLAGS) $(HARDENED_CXXFLAGS) $(WARN_CXXFLAGS) $(NOWARN_CXXFLAGS) $(ERROR_CXXFLAGS) $(GPROF_CXXFLAGS) $(SANITIZER_CXXFLAGS)
@@ -15,18 +15,7 @@ AM_LIBTOOLFLAGS = --preserve-dup-deps
 PTHREAD_FLAGS = $(PTHREAD_CFLAGS) $(PTHREAD_LIBS)
 EXTRA_LIBRARIES =
 
-if EMBEDDED_UNIVALUE
-LIBUNIVALUE = univalue/libunivalue.la
-
-$(LIBUNIVALUE): $(wildcard univalue/lib/*) $(wildcard univalue/include/*)
-	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
-else
-LIBUNIVALUE = $(UNIVALUE_LIBS)
-endif
-
-BITCOIN_INCLUDES=-I$(builddir) -I$(srcdir)/secp256k1/include $(BDB_CPPFLAGS) $(BOOST_CPPFLAGS) $(LEVELDB_CPPFLAGS)
-
-BITCOIN_INCLUDES += $(UNIVALUE_CFLAGS)
+BITCOIN_INCLUDES=-I$(builddir) -I$(srcdir)/secp256k1/include -I$(srcdir)/$(UNIVALUE_INCLUDE_DIR_INT) $(BDB_CPPFLAGS) $(BOOST_CPPFLAGS) $(LEVELDB_CPPFLAGS)
 
 LIBBITCOIN_SERVER=libbitcoin_server.a
 LIBBITCOIN_COMMON=libbitcoin_common.a
@@ -80,6 +69,7 @@ EXTRA_LIBRARIES += \
   $(LIBBITCOIN_ZMQ)
 
 lib_LTLIBRARIES = $(LIBBITCOINCONSENSUS)
+noinst_LTLIBRARIES =
 
 bin_PROGRAMS =
 noinst_PROGRAMS =
@@ -797,7 +787,6 @@ $(top_srcdir)/$(subdir)/config/bitcoin-config.h.in:  $(am__configure_deps)
 
 clean-local:
 	-$(MAKE) -C secp256k1 clean
-	-$(MAKE) -C univalue clean
 	-rm -f leveldb/*/*.gcda leveldb/*/*.gcno leveldb/helpers/memenv/*.gcda leveldb/helpers/memenv/*.gcno
 	-rm -f config.h
 	-rm -rf test/__pycache__
@@ -875,3 +864,5 @@ endif
 if ENABLE_QT_TESTS
 include Makefile.qttest.include
 endif
+
+include Makefile.univalue.include
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index d70793ffa9..27f9382631 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -350,8 +350,26 @@ if ENABLE_BENCH
 endif
 endif
 	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C secp256k1 check
-if EMBEDDED_UNIVALUE
-	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C univalue check
+
+if !ENABLE_FUZZ
+UNIVALUE_TESTS = univalue/test/object univalue/test/unitester univalue/test/no_nul
+noinst_PROGRAMS += $(UNIVALUE_TESTS)
+TESTS += $(UNIVALUE_TESTS)
+
+univalue_test_unitester_SOURCES = $(UNIVALUE_TEST_UNITESTER_INT)
+univalue_test_unitester_LDADD = $(LIBUNIVALUE)
+univalue_test_unitester_CPPFLAGS = -I$(srcdir)/$(UNIVALUE_INCLUDE_DIR_INT) -DJSON_TEST_SRC=\"$(srcdir)/$(UNIVALUE_TEST_DATA_DIR_INT)\"
+univalue_test_unitester_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
+
+univalue_test_no_nul_SOURCES = $(UNIVALUE_TEST_NO_NUL_INT)
+univalue_test_no_nul_LDADD = $(LIBUNIVALUE)
+univalue_test_no_nul_CPPFLAGS = -I$(srcdir)/$(UNIVALUE_INCLUDE_DIR_INT)
+univalue_test_no_nul_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
+
+univalue_test_object_SOURCES = $(UNIVALUE_TEST_OBJECT_INT)
+univalue_test_object_LDADD = $(LIBUNIVALUE)
+univalue_test_object_CPPFLAGS = -I$(srcdir)/$(UNIVALUE_INCLUDE_DIR_INT)
+univalue_test_object_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
 endif
 
 %.cpp.test: %.cpp
diff --git a/src/Makefile.univalue.include b/src/Makefile.univalue.include
new file mode 100644
index 0000000000..3644e36368
--- /dev/null
+++ b/src/Makefile.univalue.include
@@ -0,0 +1,6 @@
+include univalue/sources.mk
+
+LIBUNIVALUE = libunivalue.la
+noinst_LTLIBRARIES += $(LIBUNIVALUE)
+libunivalue_la_SOURCES = $(UNIVALUE_LIB_SOURCES_INT) $(UNIVALUE_DIST_HEADERS_INT) $(UNIVALUE_LIB_HEADERS_INT) $(UNIVALUE_TEST_FILES_INT)
+libunivalue_la_CPPFLAGS = $(AM_CPPFLAGS) -I$(srcdir)/$(UNIVALUE_INCLUDE_DIR_INT)
diff --git a/src/univalue/.cirrus.yml b/src/univalue/.cirrus.yml
new file mode 100644
index 0000000000..f140fee12b
--- /dev/null
+++ b/src/univalue/.cirrus.yml
@@ -0,0 +1,44 @@
+env:
+  MAKEJOBS: "-j4"
+  RUN_TESTS: "true"
+  BASE_OUTDIR: "$CIRRUS_WORKING_DIR/out_dir_base"
+  DEBIAN_FRONTEND: "noninteractive"
+
+task:
+  container:
+    image: ubuntu:focal
+    cpu: 1
+    memory: 1G
+    greedy: true  # https://medium.com/cirruslabs/introducing-greedy-container-instances-29aad06dc2b4
+
+  matrix:
+    - name: "gcc"
+      env:
+        CC: "gcc"
+        CXX: "g++"
+        APT_PKGS: "gcc"
+    - name: "clang"
+      env:
+        CC: "clang"
+        CXX: "clang++"
+        APT_PKGS: "clang"
+    - name: "mingw"
+      env:
+        CC: ""
+        CXX: ""
+        UNIVALUE_CONFIG: "--host=x86_64-w64-mingw32"
+        APT_PKGS: "g++-mingw-w64-x86-64 gcc-mingw-w64-x86-64 binutils-mingw-w64-x86-64"
+        RUN_TESTS: "false"
+
+  install_script:
+    - apt update
+    - apt install -y pkg-config build-essential libtool autotools-dev automake bsdmainutils
+    - apt install -y $APT_PKGS
+  autogen_script:
+     - ./autogen.sh
+  configure_script:
+     - ./configure --cache-file=config.cache --bindir=$BASE_OUTDIR/bin --libdir=$BASE_OUTDIR/lib $UNIVALUE_CONFIG
+  make_script:
+     - make $MAKEJOBS V=1
+  test_script:
+     - if [ "$RUN_TESTS" = "true" ]; then make $MAKEJOBS distcheck; fi
diff --git a/src/univalue/.travis.yml b/src/univalue/.travis.yml
deleted file mode 100644
index 43a1ed362e..0000000000
--- a/src/univalue/.travis.yml
+++ /dev/null
@@ -1,51 +0,0 @@
-language: cpp
-
-compiler:
-  - clang
-  - gcc
-
-os:
-  - linux
-  - osx
-
-sudo: false
-
-env:
-  global:
-    - MAKEJOBS=-j3
-    - RUN_TESTS=true
-    - BASE_OUTDIR=$TRAVIS_BUILD_DIR/out
-
-cache:
-  apt: true
-
-addons:
-  apt:
-    packages:
-      - pkg-config
-
-before_script:
-  - if [ -n "$USE_SHELL" ]; then export CONFIG_SHELL="$USE_SHELL"; fi
-  - test -n "$USE_SHELL" && eval '"$USE_SHELL" -c "./autogen.sh"' || ./autogen.sh
-
-script:
-  - if [ -n "$UNIVALUE_CONFIG" ]; then unset CC; unset CXX; fi
-  - OUTDIR=$BASE_OUTDIR/$TRAVIS_PULL_REQUEST/$TRAVIS_JOB_NUMBER-$HOST
-  - UNIVALUE_CONFIG_ALL="--prefix=$TRAVIS_BUILD_DIR/depends/$HOST --bindir=$OUTDIR/bin --libdir=$OUTDIR/lib"
-  - ./configure --cache-file=config.cache $UNIVALUE_CONFIG_ALL $UNIVALUE_CONFIG || ( cat config.log && false)
-  - make -s $MAKEJOBS $GOAL || ( echo "Build failure. Verbose build follows." && make $GOAL ; false )
-  - export LD_LIBRARY_PATH=$TRAVIS_BUILD_DIR/depends/$HOST/lib
-  - if [ "$RUN_TESTS" = "true" ]; then make $MAKEJOBS distcheck; fi
-
-matrix:
-  fast_finish: true
-  include:
-    - os: linux
-      compiler: gcc
-      env: UNIVALUE_CONFIG=--host=x86_64-w64-mingw32 RUN_TESTS=false
-      addons:
-        apt:
-          packages:
-            - g++-mingw-w64-x86-64
-            - gcc-mingw-w64-x86-64
-            - binutils-mingw-w64-x86-64
diff --git a/src/univalue/Makefile.am b/src/univalue/Makefile.am
index 0f5ba59954..476f14b922 100644
--- a/src/univalue/Makefile.am
+++ b/src/univalue/Makefile.am
@@ -1,20 +1,17 @@
+include sources.mk
 ACLOCAL_AMFLAGS = -I build-aux/m4
-.PHONY: gen
+.PHONY: gen FORCE
 .INTERMEDIATE: $(GENBIN)
 
-include_HEADERS = include/univalue.h
-noinst_HEADERS = lib/univalue_escapes.h lib/univalue_utffilter.h
+include_HEADERS = $(UNIVALUE_DIST_HEADERS_INT)
+noinst_HEADERS = $(UNIVALUE_LIB_HEADERS_INT)
 
 lib_LTLIBRARIES = libunivalue.la
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = pc/libunivalue.pc
 
-libunivalue_la_SOURCES = \
-	lib/univalue.cpp \
-	lib/univalue_get.cpp \
-	lib/univalue_read.cpp \
-	lib/univalue_write.cpp
+libunivalue_la_SOURCES = $(UNIVALUE_LIB_SOURCES_INT)
 
 libunivalue_la_LDFLAGS = \
 	-version-info $(LIBUNIVALUE_CURRENT):$(LIBUNIVALUE_REVISION):$(LIBUNIVALUE_AGE) \
@@ -30,89 +27,32 @@ $(GENBIN): $(GEN_SRCS)
 	@echo Building $@
 	$(AM_V_at)c++ -I$(top_srcdir)/include -o $@ $<
 
-gen: lib/univalue_escapes.h $(GENBIN)
-	@echo Updating $<
+gen: $(GENBIN) FORCE
+	@echo Updating lib/univalue_escapes.h
 	$(AM_V_at)$(GENBIN) > lib/univalue_escapes.h
 
 noinst_PROGRAMS = $(TESTS) test/test_json
 
-TEST_DATA_DIR=test
-
-test_unitester_SOURCES = test/unitester.cpp
+test_unitester_SOURCES = $(UNIVALUE_TEST_UNITESTER_INT)
 test_unitester_LDADD = libunivalue.la
-test_unitester_CXXFLAGS = -I$(top_srcdir)/include -DJSON_TEST_SRC=\"$(srcdir)/$(TEST_DATA_DIR)\"
+test_unitester_CXXFLAGS = -I$(top_srcdir)/include -DJSON_TEST_SRC=\"$(srcdir)/$(UNIVALUE_TEST_DATA_DIR_INT)\"
 test_unitester_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
 
-test_test_json_SOURCES = test/test_json.cpp
+test_test_json_SOURCES = $(UNIVALUE_TEST_JSON_INT)
 test_test_json_LDADD = libunivalue.la
 test_test_json_CXXFLAGS = -I$(top_srcdir)/include
 test_test_json_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
 
-test_no_nul_SOURCES = test/no_nul.cpp
+test_no_nul_SOURCES = $(UNIVALUE_TEST_NO_NUL_INT)
 test_no_nul_LDADD = libunivalue.la
 test_no_nul_CXXFLAGS = -I$(top_srcdir)/include
 test_no_nul_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
 
-test_object_SOURCES = test/object.cpp
+test_object_SOURCES = $(UNIVALUE_TEST_OBJECT_INT)
 test_object_LDADD = libunivalue.la
 test_object_CXXFLAGS = -I$(top_srcdir)/include
 test_object_LDFLAGS = -static $(LIBTOOL_APP_LDFLAGS)
 
-TEST_FILES = \
-	$(TEST_DATA_DIR)/fail10.json \
-	$(TEST_DATA_DIR)/fail11.json \
-	$(TEST_DATA_DIR)/fail12.json \
-	$(TEST_DATA_DIR)/fail13.json \
-	$(TEST_DATA_DIR)/fail14.json \
-	$(TEST_DATA_DIR)/fail15.json \
-	$(TEST_DATA_DIR)/fail16.json \
-	$(TEST_DATA_DIR)/fail17.json \
-	$(TEST_DATA_DIR)/fail18.json \
-	$(TEST_DATA_DIR)/fail19.json \
-	$(TEST_DATA_DIR)/fail1.json \
-	$(TEST_DATA_DIR)/fail20.json \
-	$(TEST_DATA_DIR)/fail21.json \
-	$(TEST_DATA_DIR)/fail22.json \
-	$(TEST_DATA_DIR)/fail23.json \
-	$(TEST_DATA_DIR)/fail24.json \
-	$(TEST_DATA_DIR)/fail25.json \
-	$(TEST_DATA_DIR)/fail26.json \
-	$(TEST_DATA_DIR)/fail27.json \
-	$(TEST_DATA_DIR)/fail28.json \
-	$(TEST_DATA_DIR)/fail29.json \
-	$(TEST_DATA_DIR)/fail2.json \
-	$(TEST_DATA_DIR)/fail30.json \
-	$(TEST_DATA_DIR)/fail31.json \
-	$(TEST_DATA_DIR)/fail32.json \
-	$(TEST_DATA_DIR)/fail33.json \
-	$(TEST_DATA_DIR)/fail34.json \
-	$(TEST_DATA_DIR)/fail35.json \
-	$(TEST_DATA_DIR)/fail36.json \
-	$(TEST_DATA_DIR)/fail37.json \
-	$(TEST_DATA_DIR)/fail38.json \
-	$(TEST_DATA_DIR)/fail39.json \
-	$(TEST_DATA_DIR)/fail40.json \
-	$(TEST_DATA_DIR)/fail41.json \
-	$(TEST_DATA_DIR)/fail42.json \
-	$(TEST_DATA_DIR)/fail44.json \
-	$(TEST_DATA_DIR)/fail45.json \
-	$(TEST_DATA_DIR)/fail3.json \
-	$(TEST_DATA_DIR)/fail4.json \
-	$(TEST_DATA_DIR)/fail5.json \
-	$(TEST_DATA_DIR)/fail6.json \
-	$(TEST_DATA_DIR)/fail7.json \
-	$(TEST_DATA_DIR)/fail8.json \
-	$(TEST_DATA_DIR)/fail9.json \
-	$(TEST_DATA_DIR)/pass1.json \
-	$(TEST_DATA_DIR)/pass2.json \
-	$(TEST_DATA_DIR)/pass3.json \
-	$(TEST_DATA_DIR)/pass4.json \
-	$(TEST_DATA_DIR)/round1.json \
-	$(TEST_DATA_DIR)/round2.json \
-	$(TEST_DATA_DIR)/round3.json \
-	$(TEST_DATA_DIR)/round4.json \
-	$(TEST_DATA_DIR)/round5.json \
-	$(TEST_DATA_DIR)/round6.json \
-	$(TEST_DATA_DIR)/round7.json
-
-EXTRA_DIST=$(TEST_FILES) $(GEN_SRCS)
+TEST_FILES = $(UNIVALUE_TEST_FILES_INT)
+
+EXTRA_DIST=$(UNIVALUE_TEST_FILES_INT) $(GEN_SRCS)
diff --git a/src/univalue/build-aux/m4/ax_cxx_compile_stdcxx.m4 b/src/univalue/build-aux/m4/ax_cxx_compile_stdcxx.m4
new file mode 100644
index 0000000000..f7e5137003
--- /dev/null
+++ b/src/univalue/build-aux/m4/ax_cxx_compile_stdcxx.m4
@@ -0,0 +1,962 @@
+# ===========================================================================
+#  https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
+#
+# DESCRIPTION
+#
+#   Check for baseline language coverage in the compiler for the specified
+#   version of the C++ standard.  If necessary, add switches to CXX and
+#   CXXCPP to enable support.  VERSION may be '11' (for the C++11 standard)
+#   or '14' (for the C++14 standard).
+#
+#   The second argument, if specified, indicates whether you insist on an
+#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
+#   -std=c++11).  If neither is specified, you get whatever works, with
+#   preference for no added switch, and then for an extended mode.
+#
+#   The third argument, if specified 'mandatory' or if left unspecified,
+#   indicates that baseline support for the specified C++ standard is
+#   required and that the macro should error out if no mode with that
+#   support is found.  If specified 'optional', then configuration proceeds
+#   regardless, after defining HAVE_CXX${VERSION} if and only if a
+#   supporting mode is found.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
+#   Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
+#   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
+#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
+#   Copyright (c) 2015 Paul Norman <penorman@mac.com>
+#   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
+#   Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
+#   Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
+#   Copyright (c) 2020 Jason Merrill <jason@redhat.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.  This file is offered as-is, without any
+#   warranty.
+
+#serial 12
+
+dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
+dnl  (serial version number 13).
+
+AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
+  m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"],
+        [$1], [14], [ax_cxx_compile_alternatives="14 1y"],
+        [$1], [17], [ax_cxx_compile_alternatives="17 1z"],
+        [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
+  m4_if([$2], [], [],
+        [$2], [ext], [],
+        [$2], [noext], [],
+        [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
+  m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
+        [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
+        [$3], [optional], [ax_cxx_compile_cxx$1_required=false],
+        [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
+  AC_LANG_PUSH([C++])dnl
+  ac_success=no
+
+  m4_if([$2], [], [dnl
+    AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+       ax_cv_cxx_compile_cxx$1,
+      [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+        [ax_cv_cxx_compile_cxx$1=yes],
+        [ax_cv_cxx_compile_cxx$1=no])])
+    if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+      ac_success=yes
+    fi])
+
+  m4_if([$2], [noext], [], [dnl
+  if test x$ac_success = xno; then
+    for alternative in ${ax_cxx_compile_alternatives}; do
+      switch="-std=gnu++${alternative}"
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+                     $cachevar,
+        [ac_save_CXX="$CXX"
+         CXX="$CXX $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXX="$ac_save_CXX"])
+      if eval test x\$$cachevar = xyes; then
+        CXX="$CXX $switch"
+        if test -n "$CXXCPP" ; then
+          CXXCPP="$CXXCPP $switch"
+        fi
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+
+  m4_if([$2], [ext], [], [dnl
+  if test x$ac_success = xno; then
+    dnl HP's aCC needs +std=c++11 according to:
+    dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
+    dnl Cray's crayCC needs "-h std=c++11"
+    for alternative in ${ax_cxx_compile_alternatives}; do
+      for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do
+        cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+        AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+                       $cachevar,
+          [ac_save_CXX="$CXX"
+           CXX="$CXX $switch"
+           AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+            [eval $cachevar=yes],
+            [eval $cachevar=no])
+           CXX="$ac_save_CXX"])
+        if eval test x\$$cachevar = xyes; then
+          CXX="$CXX $switch"
+          if test -n "$CXXCPP" ; then
+            CXXCPP="$CXXCPP $switch"
+          fi
+          ac_success=yes
+          break
+        fi
+      done
+      if test x$ac_success = xyes; then
+        break
+      fi
+    done
+  fi])
+  AC_LANG_POP([C++])
+  if test x$ax_cxx_compile_cxx$1_required = xtrue; then
+    if test x$ac_success = xno; then
+      AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
+    fi
+  fi
+  if test x$ac_success = xno; then
+    HAVE_CXX$1=0
+    AC_MSG_NOTICE([No compiler with C++$1 support was found])
+  else
+    HAVE_CXX$1=1
+    AC_DEFINE(HAVE_CXX$1,1,
+              [define if the compiler supports basic C++$1 syntax])
+  fi
+  AC_SUBST(HAVE_CXX$1)
+])
+
+
+dnl  Test body for checking C++11 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+)
+
+
+dnl  Test body for checking C++14 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+)
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
+)
+
+dnl  Tests for new features in C++11
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201103L
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+  namespace test_static_assert
+  {
+
+    template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+  }
+
+  namespace test_final_override
+  {
+
+    struct Base
+    {
+      virtual ~Base() {}
+      virtual void f() {}
+    };
+
+    struct Derived : public Base
+    {
+      virtual ~Derived() override {}
+      virtual void f() override {}
+    };
+
+  }
+
+  namespace test_double_right_angle_brackets
+  {
+
+    template < typename T >
+    struct check {};
+
+    typedef check<void> single_type;
+    typedef check<check<void>> double_type;
+    typedef check<check<check<void>>> triple_type;
+    typedef check<check<check<check<void>>>> quadruple_type;
+
+  }
+
+  namespace test_decltype
+  {
+
+    int
+    f()
+    {
+      int a = 1;
+      decltype(a) b = 2;
+      return a + b;
+    }
+
+  }
+
+  namespace test_type_deduction
+  {
+
+    template < typename T1, typename T2 >
+    struct is_same
+    {
+      static const bool value = false;
+    };
+
+    template < typename T >
+    struct is_same<T, T>
+    {
+      static const bool value = true;
+    };
+
+    template < typename T1, typename T2 >
+    auto
+    add(T1 a1, T2 a2) -> decltype(a1 + a2)
+    {
+      return a1 + a2;
+    }
+
+    int
+    test(const int c, volatile int v)
+    {
+      static_assert(is_same<int, decltype(0)>::value == true, "");
+      static_assert(is_same<int, decltype(c)>::value == false, "");
+      static_assert(is_same<int, decltype(v)>::value == false, "");
+      auto ac = c;
+      auto av = v;
+      auto sumi = ac + av + 'x';
+      auto sumf = ac + av + 1.0;
+      static_assert(is_same<int, decltype(ac)>::value == true, "");
+      static_assert(is_same<int, decltype(av)>::value == true, "");
+      static_assert(is_same<int, decltype(sumi)>::value == true, "");
+      static_assert(is_same<int, decltype(sumf)>::value == false, "");
+      static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+      return (sumf > 0.0) ? sumi : add(c, v);
+    }
+
+  }
+
+  namespace test_noexcept
+  {
+
+    int f() { return 0; }
+    int g() noexcept { return 0; }
+
+    static_assert(noexcept(f()) == false, "");
+    static_assert(noexcept(g()) == true, "");
+
+  }
+
+  namespace test_constexpr
+  {
+
+    template < typename CharT >
+    unsigned long constexpr
+    strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+    {
+      return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+    }
+
+    template < typename CharT >
+    unsigned long constexpr
+    strlen_c(const CharT *const s) noexcept
+    {
+      return strlen_c_r(s, 0UL);
+    }
+
+    static_assert(strlen_c("") == 0UL, "");
+    static_assert(strlen_c("1") == 1UL, "");
+    static_assert(strlen_c("example") == 7UL, "");
+    static_assert(strlen_c("another\0example") == 7UL, "");
+
+  }
+
+  namespace test_rvalue_references
+  {
+
+    template < int N >
+    struct answer
+    {
+      static constexpr int value = N;
+    };
+
+    answer<1> f(int&)       { return answer<1>(); }
+    answer<2> f(const int&) { return answer<2>(); }
+    answer<3> f(int&&)      { return answer<3>(); }
+
+    void
+    test()
+    {
+      int i = 0;
+      const int c = 0;
+      static_assert(decltype(f(i))::value == 1, "");
+      static_assert(decltype(f(c))::value == 2, "");
+      static_assert(decltype(f(0))::value == 3, "");
+    }
+
+  }
+
+  namespace test_uniform_initialization
+  {
+
+    struct test
+    {
+      static const int zero {};
+      static const int one {1};
+    };
+
+    static_assert(test::zero == 0, "");
+    static_assert(test::one == 1, "");
+
+  }
+
+  namespace test_lambdas
+  {
+
+    void
+    test1()
+    {
+      auto lambda1 = [](){};
+      auto lambda2 = lambda1;
+      lambda1();
+      lambda2();
+    }
+
+    int
+    test2()
+    {
+      auto a = [](int i, int j){ return i + j; }(1, 2);
+      auto b = []() -> int { return '0'; }();
+      auto c = [=](){ return a + b; }();
+      auto d = [&](){ return c; }();
+      auto e = [a, &b](int x) mutable {
+        const auto identity = [](int y){ return y; };
+        for (auto i = 0; i < a; ++i)
+          a += b--;
+        return x + identity(a + b);
+      }(0);
+      return a + b + c + d + e;
+    }
+
+    int
+    test3()
+    {
+      const auto nullary = [](){ return 0; };
+      const auto unary = [](int x){ return x; };
+      using nullary_t = decltype(nullary);
+      using unary_t = decltype(unary);
+      const auto higher1st = [](nullary_t f){ return f(); };
+      const auto higher2nd = [unary](nullary_t f1){
+        return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+      };
+      return higher1st(nullary) + higher2nd(nullary)(unary);
+    }
+
+  }
+
+  namespace test_variadic_templates
+  {
+
+    template <int...>
+    struct sum;
+
+    template <int N0, int... N1toN>
+    struct sum<N0, N1toN...>
+    {
+      static constexpr auto value = N0 + sum<N1toN...>::value;
+    };
+
+    template <>
+    struct sum<>
+    {
+      static constexpr auto value = 0;
+    };
+
+    static_assert(sum<>::value == 0, "");
+    static_assert(sum<1>::value == 1, "");
+    static_assert(sum<23>::value == 23, "");
+    static_assert(sum<1, 2>::value == 3, "");
+    static_assert(sum<5, 5, 11>::value == 21, "");
+    static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+  }
+
+  // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+  // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+  // because of this.
+  namespace test_template_alias_sfinae
+  {
+
+    struct foo {};
+
+    template<typename T>
+    using member = typename T::member_type;
+
+    template<typename T>
+    void func(...) {}
+
+    template<typename T>
+    void func(member<T>*) {}
+
+    void test();
+
+    void test() { func<foo>(0); }
+
+  }
+
+}  // namespace cxx11
+
+#endif  // __cplusplus >= 201103L
+
+]])
+
+
+dnl  Tests for new features in C++14
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
+
+// If the compiler admits that it is not ready for C++14, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201402L
+
+#error "This is not a C++14 compiler"
+
+#else
+
+namespace cxx14
+{
+
+  namespace test_polymorphic_lambdas
+  {
+
+    int
+    test()
+    {
+      const auto lambda = [](auto&&... args){
+        const auto istiny = [](auto x){
+          return (sizeof(x) == 1UL) ? 1 : 0;
+        };
+        const int aretiny[] = { istiny(args)... };
+        return aretiny[0];
+      };
+      return lambda(1, 1L, 1.0f, '1');
+    }
+
+  }
+
+  namespace test_binary_literals
+  {
+
+    constexpr auto ivii = 0b0000000000101010;
+    static_assert(ivii == 42, "wrong value");
+
+  }
+
+  namespace test_generalized_constexpr
+  {
+
+    template < typename CharT >
+    constexpr unsigned long
+    strlen_c(const CharT *const s) noexcept
+    {
+      auto length = 0UL;
+      for (auto p = s; *p; ++p)
+        ++length;
+      return length;
+    }
+
+    static_assert(strlen_c("") == 0UL, "");
+    static_assert(strlen_c("x") == 1UL, "");
+    static_assert(strlen_c("test") == 4UL, "");
+    static_assert(strlen_c("another\0test") == 7UL, "");
+
+  }
+
+  namespace test_lambda_init_capture
+  {
+
+    int
+    test()
+    {
+      auto x = 0;
+      const auto lambda1 = [a = x](int b){ return a + b; };
+      const auto lambda2 = [a = lambda1(x)](){ return a; };
+      return lambda2();
+    }
+
+  }
+
+  namespace test_digit_separators
+  {
+
+    constexpr auto ten_million = 100'000'000;
+    static_assert(ten_million == 100000000, "");
+
+  }
+
+  namespace test_return_type_deduction
+  {
+
+    auto f(int& x) { return x; }
+    decltype(auto) g(int& x) { return x; }
+
+    template < typename T1, typename T2 >
+    struct is_same
+    {
+      static constexpr auto value = false;
+    };
+
+    template < typename T >
+    struct is_same<T, T>
+    {
+      static constexpr auto value = true;
+    };
+
+    int
+    test()
+    {
+      auto x = 0;
+      static_assert(is_same<int, decltype(f(x))>::value, "");
+      static_assert(is_same<int&, decltype(g(x))>::value, "");
+      return x;
+    }
+
+  }
+
+}  // namespace cxx14
+
+#endif  // __cplusplus >= 201402L
+
+]])
+
+
+dnl  Tests for new features in C++17
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[
+
+// If the compiler admits that it is not ready for C++17, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201703L
+
+#error "This is not a C++17 compiler"
+
+#else
+
+#include <initializer_list>
+#include <utility>
+#include <type_traits>
+
+namespace cxx17
+{
+
+  namespace test_constexpr_lambdas
+  {
+
+    constexpr int foo = [](){return 42;}();
+
+  }
+
+  namespace test::nested_namespace::definitions
+  {
+
+  }
+
+  namespace test_fold_expression
+  {
+
+    template<typename... Args>
+    int multiply(Args... args)
+    {
+      return (args * ... * 1);
+    }
+
+    template<typename... Args>
+    bool all(Args... args)
+    {
+      return (args && ...);
+    }
+
+  }
+
+  namespace test_extended_static_assert
+  {
+
+    static_assert (true);
+
+  }
+
+  namespace test_auto_brace_init_list
+  {
+
+    auto foo = {5};
+    auto bar {5};
+
+    static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value);
+    static_assert(std::is_same<int, decltype(bar)>::value);
+  }
+
+  namespace test_typename_in_template_template_parameter
+  {
+
+    template<template<typename> typename X> struct D;
+
+  }
+
+  namespace test_fallthrough_nodiscard_maybe_unused_attributes
+  {
+
+    int f1()
+    {
+      return 42;
+    }
+
+    [[nodiscard]] int f2()
+    {
+      [[maybe_unused]] auto unused = f1();
+
+      switch (f1())
+      {
+      case 17:
+        f1();
+        [[fallthrough]];
+      case 42:
+        f1();
+      }
+      return f1();
+    }
+
+  }
+
+  namespace test_extended_aggregate_initialization
+  {
+
+    struct base1
+    {
+      int b1, b2 = 42;
+    };
+
+    struct base2
+    {
+      base2() {
+        b3 = 42;
+      }
+      int b3;
+    };
+
+    struct derived : base1, base2
+    {
+        int d;
+    };
+
+    derived d1 {{1, 2}, {}, 4};  // full initialization
+    derived d2 {{}, {}, 4};      // value-initialized bases
+
+  }
+
+  namespace test_general_range_based_for_loop
+  {
+
+    struct iter
+    {
+      int i;
+
+      int& operator* ()
+      {
+        return i;
+      }
+
+      const int& operator* () const
+      {
+        return i;
+      }
+
+      iter& operator++()
+      {
+        ++i;
+        return *this;
+      }
+    };
+
+    struct sentinel
+    {
+      int i;
+    };
+
+    bool operator== (const iter& i, const sentinel& s)
+    {
+      return i.i == s.i;
+    }
+
+    bool operator!= (const iter& i, const sentinel& s)
+    {
+      return !(i == s);
+    }
+
+    struct range
+    {
+      iter begin() const
+      {
+        return {0};
+      }
+
+      sentinel end() const
+      {
+        return {5};
+      }
+    };
+
+    void f()
+    {
+      range r {};
+
+      for (auto i : r)
+      {
+        [[maybe_unused]] auto v = i;
+      }
+    }
+
+  }
+
+  namespace test_lambda_capture_asterisk_this_by_value
+  {
+
+    struct t
+    {
+      int i;
+      int foo()
+      {
+        return [*this]()
+        {
+          return i;
+        }();
+      }
+    };
+
+  }
+
+  namespace test_enum_class_construction
+  {
+
+    enum class byte : unsigned char
+    {};
+
+    byte foo {42};
+
+  }
+
+  namespace test_constexpr_if
+  {
+
+    template <bool cond>
+    int f ()
+    {
+      if constexpr(cond)
+      {
+        return 13;
+      }
+      else
+      {
+        return 42;
+      }
+    }
+
+  }
+
+  namespace test_selection_statement_with_initializer
+  {
+
+    int f()
+    {
+      return 13;
+    }
+
+    int f2()
+    {
+      if (auto i = f(); i > 0)
+      {
+        return 3;
+      }
+
+      switch (auto i = f(); i + 4)
+      {
+      case 17:
+        return 2;
+
+      default:
+        return 1;
+      }
+    }
+
+  }
+
+  namespace test_template_argument_deduction_for_class_templates
+  {
+
+    template <typename T1, typename T2>
+    struct pair
+    {
+      pair (T1 p1, T2 p2)
+        : m1 {p1},
+          m2 {p2}
+      {}
+
+      T1 m1;
+      T2 m2;
+    };
+
+    void f()
+    {
+      [[maybe_unused]] auto p = pair{13, 42u};
+    }
+
+  }
+
+  namespace test_non_type_auto_template_parameters
+  {
+
+    template <auto n>
+    struct B
+    {};
+
+    B<5> b1;
+    B<'a'> b2;
+
+  }
+
+  namespace test_structured_bindings
+  {
+
+    int arr[2] = { 1, 2 };
+    std::pair<int, int> pr = { 1, 2 };
+
+    auto f1() -> int(&)[2]
+    {
+      return arr;
+    }
+
+    auto f2() -> std::pair<int, int>&
+    {
+      return pr;
+    }
+
+    struct S
+    {
+      int x1 : 2;
+      volatile double y1;
+    };
+
+    S f3()
+    {
+      return {};
+    }
+
+    auto [ x1, y1 ] = f1();
+    auto& [ xr1, yr1 ] = f1();
+    auto [ x2, y2 ] = f2();
+    auto& [ xr2, yr2 ] = f2();
+    const auto [ x3, y3 ] = f3();
+
+  }
+
+  namespace test_exception_spec_type_system
+  {
+
+    struct Good {};
+    struct Bad {};
+
+    void g1() noexcept;
+    void g2();
+
+    template<typename T>
+    Bad
+    f(T*, T*);
+
+    template<typename T1, typename T2>
+    Good
+    f(T1*, T2*);
+
+    static_assert (std::is_same_v<Good, decltype(f(g1, g2))>);
+
+  }
+
+  namespace test_inline_variables
+  {
+
+    template<class T> void f(T)
+    {}
+
+    template<class T> inline T g(T)
+    {
+      return T{};
+    }
+
+    template<> inline void f<>(int)
+    {}
+
+    template<> int g<>(int)
+    {
+      return 5;
+    }
+
+  }
+
+}  // namespace cxx17
+
+#endif  // __cplusplus < 201703L
+
+]])
diff --git a/src/univalue/configure.ac b/src/univalue/configure.ac
index 8298332ac1..495b25a53d 100644
--- a/src/univalue/configure.ac
+++ b/src/univalue/configure.ac
@@ -1,7 +1,7 @@
 m4_define([libunivalue_major_version], [1])
 m4_define([libunivalue_minor_version], [1])
-m4_define([libunivalue_micro_version], [3])
-m4_define([libunivalue_interface_age], [3])
+m4_define([libunivalue_micro_version], [4])
+m4_define([libunivalue_interface_age], [4])
 # If you need a modifier for the version number. 
 # Normally empty, but can be used to make "fixup" releases.
 m4_define([libunivalue_extraversion], [])
@@ -14,7 +14,7 @@ m4_define([libunivalue_age], [m4_eval(libunivalue_binary_age - libunivalue_inter
 m4_define([libunivalue_version], [libunivalue_major_version().libunivalue_minor_version().libunivalue_micro_version()libunivalue_extraversion()])
 
 
-AC_INIT([univalue], [1.0.3],
+AC_INIT([univalue], [1.0.4],
         [http://github.com/jgarzik/univalue/])
 
 dnl make the compilation flags quiet unless V=1 is used
@@ -45,6 +45,9 @@ AC_SUBST(LIBUNIVALUE_AGE)
 LT_INIT
 LT_LANG([C++])
 
+dnl Require C++11 compiler (no GNU extensions)
+AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory], [nodefault])
+
 case $host in
   *mingw*)
     LIBTOOL_APP_LDFLAGS="$LIBTOOL_APP_LDFLAGS -all-static"
diff --git a/src/univalue/gen/gen.cpp b/src/univalue/gen/gen.cpp
index 85fe20924a..b8a6c73f4e 100644
--- a/src/univalue/gen/gen.cpp
+++ b/src/univalue/gen/gen.cpp
@@ -1,6 +1,6 @@
 // Copyright 2014 BitPay Inc.
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 //
 // To re-create univalue_escapes.h:
@@ -45,7 +45,7 @@ static void outputEscape()
 
 	for (unsigned int i = 0; i < 256; i++) {
 		if (escapes[i].empty()) {
-			printf("\tNULL,\n");
+			printf("\tnullptr,\n");
 		} else {
 			printf("\t\"");
 
diff --git a/src/univalue/include/univalue.h b/src/univalue/include/univalue.h
index 048e162f7d..fc5cf402be 100644
--- a/src/univalue/include/univalue.h
+++ b/src/univalue/include/univalue.h
@@ -1,7 +1,7 @@
 // Copyright 2014 BitPay Inc.
 // Copyright 2015 Bitcoin Core Developers
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #ifndef __UNIVALUE_H__
 #define __UNIVALUE_H__
@@ -14,8 +14,6 @@
 #include <map>
 #include <cassert>
 
-#include <sstream>        // .get_int64()
-
 class UniValue {
 public:
     enum VType { VNULL, VOBJ, VARR, VSTR, VNUM, VBOOL, };
diff --git a/src/univalue/lib/univalue.cpp b/src/univalue/lib/univalue.cpp
index 4c9c15d63e..c4e59fae74 100644
--- a/src/univalue/lib/univalue.cpp
+++ b/src/univalue/lib/univalue.cpp
@@ -1,7 +1,7 @@
 // Copyright 2014 BitPay Inc.
 // Copyright 2015 Bitcoin Core Developers
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #include <stdint.h>
 #include <iomanip>
@@ -178,17 +178,19 @@ bool UniValue::findKey(const std::string& key, size_t& retIdx) const
 
 bool UniValue::checkObject(const std::map<std::string,UniValue::VType>& t) const
 {
-    if (typ != VOBJ)
+    if (typ != VOBJ) {
         return false;
+    }
 
-    for (std::map<std::string,UniValue::VType>::const_iterator it = t.begin();
-         it != t.end(); ++it) {
+    for (const auto& object: t) {
         size_t idx = 0;
-        if (!findKey(it->first, idx))
+        if (!findKey(object.first, idx)) {
             return false;
+        }
 
-        if (values.at(idx).getType() != it->second)
+        if (values.at(idx).getType() != object.second) {
             return false;
+        }
     }
 
     return true;
@@ -228,7 +230,7 @@ const char *uvTypeName(UniValue::VType t)
     }
 
     // not reached
-    return NULL;
+    return nullptr;
 }
 
 const UniValue& find_value(const UniValue& obj, const std::string& name)
diff --git a/src/univalue/lib/univalue_escapes.h b/src/univalue/lib/univalue_escapes.h
index 74596aab6d..3f714f8e5b 100644
--- a/src/univalue/lib/univalue_escapes.h
+++ b/src/univalue/lib/univalue_escapes.h
@@ -34,229 +34,229 @@ static const char *escapes[256] = {
 	"\\u001d",
 	"\\u001e",
 	"\\u001f",
-	NULL,
-	NULL,
+	nullptr,
+	nullptr,
 	"\\\"",
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
 	"\\\\",
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
 	"\\u007f",
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
 };
 #endif // BITCOIN_UNIVALUE_UNIVALUE_ESCAPES_H
diff --git a/src/univalue/lib/univalue_get.cpp b/src/univalue/lib/univalue_get.cpp
index 0ad6146545..5af89a3561 100644
--- a/src/univalue/lib/univalue_get.cpp
+++ b/src/univalue/lib/univalue_get.cpp
@@ -1,7 +1,7 @@
 // Copyright 2014 BitPay Inc.
 // Copyright 2015 Bitcoin Core Developers
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #include <stdint.h>
 #include <errno.h>
@@ -11,6 +11,7 @@
 #include <vector>
 #include <limits>
 #include <string>
+#include <sstream>
 
 #include "univalue.h"
 
@@ -31,7 +32,7 @@ bool ParseInt32(const std::string& str, int32_t *out)
 {
     if (!ParsePrechecks(str))
         return false;
-    char *endp = NULL;
+    char *endp = nullptr;
     errno = 0; // strtol will not set errno if valid
     long int n = strtol(str.c_str(), &endp, 10);
     if(out) *out = (int32_t)n;
@@ -47,7 +48,7 @@ bool ParseInt64(const std::string& str, int64_t *out)
 {
     if (!ParsePrechecks(str))
         return false;
-    char *endp = NULL;
+    char *endp = nullptr;
     errno = 0; // strtoll will not set errno if valid
     long long int n = strtoll(str.c_str(), &endp, 10);
     if(out) *out = (int64_t)n;
diff --git a/src/univalue/lib/univalue_read.cpp b/src/univalue/lib/univalue_read.cpp
index 5c6a1acf75..be39bfe57a 100644
--- a/src/univalue/lib/univalue_read.cpp
+++ b/src/univalue/lib/univalue_read.cpp
@@ -1,6 +1,6 @@
 // Copyright 2014 BitPay Inc.
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #include <string.h>
 #include <vector>
@@ -227,7 +227,7 @@ enum jtokentype getJsonToken(std::string& tokenVal, unsigned int& consumed,
             }
 
             else {
-                writer.push_back(*raw);
+                writer.push_back(static_cast<unsigned char>(*raw));
                 raw++;
             }
         }
@@ -244,7 +244,7 @@ enum jtokentype getJsonToken(std::string& tokenVal, unsigned int& consumed,
     }
 }
 
-enum expect_bits {
+enum expect_bits : unsigned {
     EXP_OBJ_NAME = (1U << 0),
     EXP_COLON = (1U << 1),
     EXP_ARR_VALUE = (1U << 2),
diff --git a/src/univalue/lib/univalue_utffilter.h b/src/univalue/lib/univalue_utffilter.h
index 20d4043009..c24ac58eaf 100644
--- a/src/univalue/lib/univalue_utffilter.h
+++ b/src/univalue/lib/univalue_utffilter.h
@@ -1,6 +1,6 @@
 // Copyright 2016 Wladimir J. van der Laan
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 #ifndef UNIVALUE_UTFFILTER_H
 #define UNIVALUE_UTFFILTER_H
 
diff --git a/src/univalue/lib/univalue_write.cpp b/src/univalue/lib/univalue_write.cpp
index 827eb9b271..3a2c580c7f 100644
--- a/src/univalue/lib/univalue_write.cpp
+++ b/src/univalue/lib/univalue_write.cpp
@@ -1,9 +1,8 @@
 // Copyright 2014 BitPay Inc.
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #include <iomanip>
-#include <sstream>
 #include <stdio.h>
 #include "univalue.h"
 #include "univalue_escapes.h"
@@ -14,13 +13,13 @@ static std::string json_escape(const std::string& inS)
     outS.reserve(inS.size() * 2);
 
     for (unsigned int i = 0; i < inS.size(); i++) {
-        unsigned char ch = inS[i];
+        unsigned char ch = static_cast<unsigned char>(inS[i]);
         const char *escStr = escapes[ch];
 
         if (escStr)
             outS += escStr;
         else
-            outS += ch;
+            outS += static_cast<char>(ch);
     }
 
     return outS;
diff --git a/src/univalue/sources.mk b/src/univalue/sources.mk
new file mode 100644
index 0000000000..efab6d277f
--- /dev/null
+++ b/src/univalue/sources.mk
@@ -0,0 +1,95 @@
+# - All variables are namespaced with UNIVALUE_ to avoid colliding with
+#     downstream makefiles.
+# - All Variables ending in _HEADERS or _SOURCES confuse automake, so the
+#     _INT postfix is applied.
+# - Convenience variables, for example a UNIVALUE_TEST_DIR should not be used
+#     as they interfere with automatic dependency generation
+# - The %reldir% is the relative path from the Makefile.am. This allows
+#   downstreams to use these variables without having to manually account for
+#   the path change.
+
+UNIVALUE_INCLUDE_DIR_INT = %reldir%/include
+
+UNIVALUE_DIST_HEADERS_INT =
+UNIVALUE_DIST_HEADERS_INT += %reldir%/include/univalue.h
+
+UNIVALUE_LIB_HEADERS_INT =
+UNIVALUE_LIB_HEADERS_INT += %reldir%/lib/univalue_utffilter.h
+UNIVALUE_LIB_HEADERS_INT += %reldir%/lib/univalue_escapes.h
+
+UNIVALUE_LIB_SOURCES_INT =
+UNIVALUE_LIB_SOURCES_INT += %reldir%/lib/univalue.cpp
+UNIVALUE_LIB_SOURCES_INT += %reldir%/lib/univalue_get.cpp
+UNIVALUE_LIB_SOURCES_INT += %reldir%/lib/univalue_read.cpp
+UNIVALUE_LIB_SOURCES_INT += %reldir%/lib/univalue_write.cpp
+
+UNIVALUE_TEST_DATA_DIR_INT = %reldir%/test
+
+UNIVALUE_TEST_UNITESTER_INT =
+UNIVALUE_TEST_UNITESTER_INT += %reldir%/test/unitester.cpp
+
+UNIVALUE_TEST_JSON_INT =
+UNIVALUE_TEST_JSON_INT += %reldir%/test/test_json.cpp
+
+UNIVALUE_TEST_NO_NUL_INT =
+UNIVALUE_TEST_NO_NUL_INT += %reldir%/test/no_nul.cpp
+
+UNIVALUE_TEST_OBJECT_INT =
+UNIVALUE_TEST_OBJECT_INT += %reldir%/test/object.cpp
+
+UNIVALUE_TEST_FILES_INT =
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail1.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail2.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail3.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail4.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail5.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail6.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail7.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail8.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail9.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail10.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail11.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail12.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail13.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail14.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail15.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail16.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail17.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail18.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail19.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail20.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail21.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail22.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail23.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail24.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail25.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail26.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail27.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail28.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail29.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail30.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail31.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail32.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail33.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail34.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail35.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail36.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail37.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail38.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail39.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail40.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail41.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail42.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail44.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/fail45.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/pass1.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/pass2.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/pass3.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/pass4.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round1.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round2.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round3.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round4.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round5.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round6.json
+UNIVALUE_TEST_FILES_INT += %reldir%/test/round7.json
diff --git a/src/univalue/test/object.cpp b/src/univalue/test/object.cpp
index ccc1344836..c2f52f83ac 100644
--- a/src/univalue/test/object.cpp
+++ b/src/univalue/test/object.cpp
@@ -1,7 +1,7 @@
 // Copyright (c) 2014 BitPay Inc.
 // Copyright (c) 2014-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #include <stdint.h>
 #include <vector>
diff --git a/src/univalue/test/unitester.cpp b/src/univalue/test/unitester.cpp
index 2308afbcdf..02e1a83c6d 100644
--- a/src/univalue/test/unitester.cpp
+++ b/src/univalue/test/unitester.cpp
@@ -1,6 +1,6 @@
 // Copyright 2014 BitPay Inc.
 // Distributed under the MIT/X11 software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://opensource.org/licenses/mit-license.php.
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -58,7 +58,7 @@ static void runtest_file(const char *filename_)
         std::string basename(filename_);
         std::string filename = srcdir + "/" + basename;
         FILE *f = fopen(filename.c_str(), "r");
-        assert(f != NULL);
+        assert(f != nullptr);
 
         std::string jdata;