Merge pull request #3242

2041365 Bugfix: Use BOOST_CPPFLAGS when testing for boost sleep vs sleep_for (Luke Dashjr)
e18e100 configure: Minor grammatical changes to be more clear (Luke Dashjr)
a9dbcf0 configure: Change --with[out]-qt to --with[out]-gui and add --with[out]-cli and --with[out]-daemon to support more build configurations (Luke Dashjr)
f472990 Bugfix: Correct captitalisation of Qt (Luke Dashjr)
f930341 configure: Internal changes to make building bitcoind and bitcoin-cli optional (Luke Dashjr)
4a290b5 Cleanup LevelDB library dependencies (Luke Dashjr)
9b4e03b Bugfix: Undefine _FORTIFY_SOURCE before redefining it, to avoid warnings on compilers that define it by default (Luke Dashjr)
123e4f8 Bugfix: configure: Allow user-provided CXXFLAGS to override default optimisation, debug, and warning flags (Luke Dashjr)

4 files changed, 114 insertions, 48 deletions

diff --git a/configure.ac b/configure.ac
index 9737b884b4..973f4398df 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,6 +24,12 @@ m4_include([pkg.m4])
 dnl faketime breaks configure and is only needed for make. Disable it here.
 unset FAKETIME
 
+if test "x${CXXFLAGS+set}" = "xset"; then
+  CXXFLAGS_overridden=yes
+else
+  CXXFLAGS_overridden=no
+fi
+
 dnl ==============================================================
 dnl Setup for automake
 dnl ==============================================================
@@ -92,7 +98,7 @@ AC_ARG_ENABLE([hardening],
 
 AC_ARG_ENABLE([ccache],
   [AS_HELP_STRING([--enable-ccache],
-  [enable building with ccache (default is yes if ccache is found)])],
+  [use ccache for building (default is yes if ccache is found)])],
   [use_ccache=$enableval],
   [use_ccache=auto])
 
@@ -134,7 +140,9 @@ PKG_PROG_PKG_CONFIG
 ## TODO: Remove these hard-coded paths and flags. They are here for the sake of
 ##       compatibility with the legacy buildsystem.
 ##
-CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter"
+if test "x$CXXFLAGS_overridden" = "xno"; then
+  CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter"
+fi
 CPPFLAGS="$CPPFLAGS -DBOOST_SPIRIT_THREADSAFE -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS"
 
 AC_LANG_PUSH([C++])
@@ -182,7 +190,9 @@ case $host in
 
      CPPFLAGS="$CPPFLAGS -D_MT -DWIN32 -D_WINDOWS -DBOOST_THREAD_USE_LIB -D__USE_MINGW_ANSI_STDIO"
      LEVELDB_TARGET_FLAGS="TARGET_OS=OS_WINDOWS_CROSSCOMPILE"
-     CXXFLAGS="$CXXFLAGS -w"
+     if test "x$CXXFLAGS_overridden" = "xno"; then
+       CXXFLAGS="$CXXFLAGS -w"
+     fi
      ;;
   *darwin*)
      TARGET_OS=darwin
@@ -276,7 +286,12 @@ if test x$use_hardening != xno; then
   AX_CHECK_COMPILE_FLAG([-Wstack-protector],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -Wstack-protector"])
   AX_CHECK_COMPILE_FLAG([-fPIE],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -fPIE"])
 
-  AX_CHECK_PREPROC_FLAG([-D_FORTIFY_SOURCE=2],[HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -D_FORTIFY_SOURCE=2"])
+  AX_CHECK_PREPROC_FLAG([-D_FORTIFY_SOURCE=2],[
+    AX_CHECK_PREPROC_FLAG([-U_FORTIFY_SOURCE],[
+      HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -U_FORTIFY_SOURCE"
+    ])
+    HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -D_FORTIFY_SOURCE=2"
+  ])
 
   AX_CHECK_LINK_FLAG([[-Wl,--dynamicbase]], [HARDENED_LDFLAGS="$HARDENED_LDFLAGS -Wl,--dynamicbase"])
   AX_CHECK_LINK_FLAG([[-Wl,--nxcompat]], [HARDENED_LDFLAGS="$HARDENED_LDFLAGS -Wl,--nxcompat"])
@@ -313,6 +328,14 @@ AC_TRY_COMPILE([#include <sys/socket.h>],
  [ AC_MSG_RESULT(no)]
 )
 
+LEVELDB_CPPFLAGS=
+LIBLEVELDB=
+LIBMEMENV=
+AM_CONDITIONAL([EMBEDDED_LEVELDB],[true])
+AC_SUBST(LEVELDB_CPPFLAGS)
+AC_SUBST(LIBLEVELDB)
+AC_SUBST(LIBMEMENV)
+
 if test x$enable_wallet != xno; then
     dnl Check for libdb_cxx only if wallet enabled
     BITCOIN_FIND_BDB48
@@ -423,6 +446,18 @@ if test x$boost_sleep != xyes; then
   AC_MSG_ERROR(No working boost sleep implementation found. If on ubuntu 13.10 with libboost1.54-all-dev remove libboost.1.54-all-dev and use libboost1.53-all-dev)
 fi
 
+AC_ARG_WITH([cli],
+  [AS_HELP_STRING([--with-cli],
+  [with CLI (default is yes)])],
+  [build_bitcoin_cli=$withval],
+  [build_bitcoin_cli=yes])
+
+AC_ARG_WITH([daemon],
+  [AS_HELP_STRING([--with-daemon],
+  [with daemon (default is yes)])],
+  [build_bitcoind=$withval],
+  [build_bitcoind=yes])
+
 BITCOIN_QT_INIT
 
 if test x$use_pkgconfig = xyes; then
@@ -459,13 +494,21 @@ fi
 
 BITCOIN_QT_PATH_PROGS([PROTOC], [protoc],$protoc_bin_path)
 
+AC_MSG_CHECKING([whether to build bitcoind])
+AM_CONDITIONAL([BUILD_BITCOIND], [test x$build_bitcoind = xyes])
+AC_MSG_RESULT($build_bitcoind)
+
+AC_MSG_CHECKING([whether to build bitcoin-cli])
+AM_CONDITIONAL([BUILD_BITCOIN_CLI], [test x$build_bitcoin_cli = xyes])
+AC_MSG_RESULT($build_bitcoin_cli)
+
 dnl sets $bitcoin_enable_qt, $bitcoin_enable_qt_test, $bitcoin_enable_qt_dbus
 BITCOIN_QT_CONFIGURE([$use_pkgconfig], [qt4])
 
 
 if test x$use_ipv6 = xyes; then
   dnl Check for ipv6 build requirements
-  AC_MSG_CHECKING(for IPV6 build support)
+  AC_MSG_CHECKING(for operating system IPv6 support)
   AC_TRY_LINK([
   #if defined(_WINDOWS)
   #include <winsock2.h>
@@ -480,18 +523,17 @@ if test x$use_ipv6 = xyes; then
   struct sockaddr_in6 addr;
   #endif
   int temp = socket(AF_INET6, SOCK_STREAM, 0);],
-  [AC_MSG_RESULT(yes); have_ipv6=yes; AC_DEFINE(HAVE_IPV6, 1, [Define this symbol if you have ipv6 build support])],
+  [AC_MSG_RESULT(yes); have_ipv6=yes; AC_DEFINE(HAVE_IPV6, 1, [Define this symbol if you have operating system IPv6 support])],
   [AC_MSG_RESULT(no)]; have_ipv6=no)
 fi
 AC_LANG_POP
 
 if test "x$use_ccache" != "xno"; then
-  AC_MSG_CHECKING(if ccache should be enabled)
+  AC_MSG_CHECKING(if ccache should be used)
   if test x$CCACHE = x; then
     if test "x$use_ccache" = "xyes"; then
       AC_MSG_ERROR([ccache not found.]);
     else
-      AC_MSG_NOTICE([ccache not found. Falling back to default CC])
       use_ccache=no
     fi
   else
@@ -513,32 +555,32 @@ else
 fi
 
 dnl enable ipv6 support
-AC_MSG_CHECKING([if ipv6 should be enabled])
+AC_MSG_CHECKING([whether to build with support for IPv6])
 if test x$have_ipv6 = xno; then
   if test x$use_ipv6 = xyes; then
-     AC_MSG_ERROR("ipv6 requested but cannot be built. use --disable-ipv6")
+     AC_MSG_ERROR([IPv6 requested, but cannot be built. use --disable-ipv6])
   fi
   AC_MSG_RESULT(no)
 else
   if test x$use_ipv6 = xyes; then
       AC_MSG_RESULT(yes)
-      AC_DEFINE([USE_IPV6],[1],[Define if ipv6 support should be compiled in])
+      AC_DEFINE([USE_IPV6],[1],[Define if IPv6 support should be compiled in])
   else
       AC_MSG_RESULT(no)
   fi
 fi
 
 dnl enable upnp support
-AC_MSG_CHECKING([if upnp should be enabled])
+AC_MSG_CHECKING([whether to build with support for UPnP])
 if test x$have_miniupnpc = xno; then
   if test x$use_upnp = xyes; then
-     AC_MSG_ERROR("upnp requested but cannot be built. use --without-miniupnpc")
+     AC_MSG_ERROR("UPnP requested but cannot be built. use --without-miniupnpc")
   fi
   AC_MSG_RESULT(no)
 else
   if test x$use_upnp != xno; then
     AC_MSG_RESULT(yes)
-    AC_MSG_CHECKING([if upnp should be on by default])
+    AC_MSG_CHECKING([whether to build with UPnP enabled by default])
     use_upnp=yes
     upnp_setting=0
     if test x$use_upnp_default != xno; then
@@ -546,7 +588,7 @@ else
       upnp_setting=1
     fi
     AC_MSG_RESULT($use_upnp_default)
-    AC_DEFINE_UNQUOTED([USE_UPNP],[$upnp_setting],[Define to 1 for upnp runtime support])
+    AC_DEFINE_UNQUOTED([USE_UPNP],[$upnp_setting],[UPnP support not compiled if undefined, otherwise value (0 or 1) determines default state])
     if test x$TARGET_OS = xwindows; then
       CPPFLAGS="$CPPFLAGS -DSTATICLIB"
     fi
@@ -559,14 +601,14 @@ dnl these are only used when qt is enabled
 if test x$bitcoin_enable_qt != xno; then
   BUILD_QT=qt
   dnl enable dbus support
-  AC_MSG_CHECKING([if dbus should be enabled])
+  AC_MSG_CHECKING([whether to build GUI with support for D-Bus])
   if test x$bitcoin_enable_qt_dbus != xno; then
     AC_DEFINE([USE_DBUS],[1],[Define if dbus support should be compiled in])
   fi
   AC_MSG_RESULT($bitcoin_enable_qt_dbus)
 
   dnl enable qr support
-  AC_MSG_CHECKING([if qr should be enabled])
+  AC_MSG_CHECKING([whether to build GUI with support for QR codes])
   if test x$have_qrencode = xno; then
     if test x$use_qr == xyes; then
      AC_MSG_ERROR("QR support requested but cannot be built. use --without-qrencode")
@@ -586,16 +628,25 @@ if test x$bitcoin_enable_qt != xno; then
     AC_MSG_WARN("xgettext is required to update qt translations")
   fi
 
-  if test x$use_tests = xyes; then
+  AC_MSG_CHECKING([whether to build test_bitcoin-qt])
+  if test x$use_tests$bitcoin_enable_qt_test = xyesyes; then
+    AC_MSG_RESULT([yes])
     BUILD_TEST_QT="test"
-    if test x$bitcoin_enable_qt_test != xyes; then
-      AC_MSG_ERROR("QT Test lib not found. Use --disable-tests or --without-qt.")
-    fi
+  else
+    AC_MSG_RESULT([no])
   fi
 fi
 
+AC_MSG_CHECKING([whether to build test_bitcoin])
 if test x$use_tests = xyes; then
+  AC_MSG_RESULT([yes])
   BUILD_TEST="test"
+else
+  AC_MSG_RESULT([no])
+fi
+
+if test "x$use_tests$build_bitcoind$use_qt" = "xnonono"; then
+  AC_MSG_ERROR([No targets! Please specify at least one of: --enable-cli --enable-daemon --enable-gui or --enable-tests])
 fi
 
 AM_CONDITIONAL([TARGET_DARWIN], [test x$TARGET_OS = xdarwin])
diff --git a/src/Makefile.am b/src/Makefile.am
index 9917be2481..f27f16ab91 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,6 @@
 include Makefile.include
 
-AM_CPPFLAGS += -I$(top_srcdir)/src/leveldb/helpers/memenv \
-  -I$(builddir)
+AM_CPPFLAGS += -I$(builddir)
 
 noinst_LIBRARIES = \
   libbitcoin_server.a \
@@ -11,7 +10,15 @@ if ENABLE_WALLET
 noinst_LIBRARIES += libbitcoin_wallet.a
 endif
 
-bin_PROGRAMS = bitcoind bitcoin-cli
+bin_PROGRAMS =
+
+if BUILD_BITCOIND
+  bin_PROGRAMS += bitcoind
+endif
+
+if BUILD_BITCOIN_CLI
+  bin_PROGRAMS += bitcoin-cli
+endif
 
 SUBDIRS = . $(BUILD_QT) $(BUILD_TEST)
 DIST_SUBDIRS = . qt test
@@ -140,8 +147,8 @@ bitcoind_LDADD = \
   libbitcoin_server.a \
   libbitcoin_cli.a \
   libbitcoin_common.a \
-  leveldb/libleveldb.a \
-  leveldb/libmemenv.a
+  $(LIBLEVELDB) \
+  $(LIBMEMENV)
 if ENABLE_WALLET
 bitcoind_LDADD += libbitcoin_wallet.a
 endif
@@ -167,6 +174,7 @@ if TARGET_WINDOWS
 bitcoin_cli_SOURCES += bitcoin-cli-res.rc
 endif
 
+# NOTE: This dependency is not strictly necessary, but without it make may try to build both in parallel, which breaks the LevelDB build system in a race
 leveldb/libleveldb.a: leveldb/libmemenv.a
 
 leveldb/%.a:
diff --git a/src/Makefile.include b/src/Makefile.include
index b9e6c262ca..01b47d1aa0 100644
--- a/src/Makefile.include
+++ b/src/Makefile.include
@@ -1,23 +1,30 @@
+if EMBEDDED_LEVELDB
+LEVELDB_CPPFLAGS += -I$(top_srcdir)/src/leveldb/include
+LEVELDB_CPPFLAGS += -I$(top_srcdir)/src/leveldb/helpers/memenv
+LIBLEVELDB += $(top_builddir)/src/leveldb/libleveldb.a
+LIBMEMENV  += $(top_builddir)/src/leveldb/libmemenv.a
+endif
+
 AM_CPPFLAGS =  $(INCLUDES) \
   -I$(top_builddir)/src/obj \
-  -I$(top_srcdir)/src/leveldb/include \
   $(BDB_CPPFLAGS) \
-  $(BOOST_INCLUDES)
+  $(BOOST_CPPFLAGS) $(BOOST_INCLUDES)
+AM_CPPFLAGS += $(LEVELDB_CPPFLAGS)
 AM_LDFLAGS = $(PTHREAD_CFLAGS)
 
 LIBBITCOIN_SERVER=$(top_builddir)/src/libbitcoin_server.a
 LIBBITCOIN_WALLET=$(top_builddir)/src/libbitcoin_wallet.a
 LIBBITCOIN_COMMON=$(top_builddir)/src/libbitcoin_common.a
 LIBBITCOIN_CLI=$(top_builddir)/src/libbitcoin_cli.a
-LIBLEVELDB=$(top_builddir)/src/leveldb/libleveldb.a
-LIBMEMENV=$(top_builddir)/src/leveldb/libmemenv.a
 LIBBITCOINQT=$(top_builddir)/src/qt/libbitcoinqt.a
 
 $(LIBBITCOIN):
 	$(MAKE) -C $(top_builddir)/src $(@F)
 
+if EMBEDDED_LEVELDB
 $(LIBLEVELDB) $(LIBMEMENV):
 	$(MAKE) -C $(top_builddir)/src leveldb/$(@F)
+endif
 
 $(LIBBITCOINQT):
 	$(MAKE) -C $(top_builddir)/src/qt $(@F)
diff --git a/src/m4/bitcoin_qt.m4 b/src/m4/bitcoin_qt.m4
index 758aea3499..5ed9692186 100644
--- a/src/m4/bitcoin_qt.m4
+++ b/src/m4/bitcoin_qt.m4
@@ -22,7 +22,7 @@ AC_DEFUN([BITCOIN_QT_CHECK],[
 ])
 
 dnl BITCOIN_QT_PATH_PROGS([FOO], [foo foo2], [/path/to/search/first], [continue if missing])
-dnl Helper for finding the path of programs needed for QT.
+dnl Helper for finding the path of programs needed for Qt.
 dnl Inputs: $1: Variable to be set
 dnl Inputs: $2: List of programs to search for
 dnl Inputs: $3: Look for $2 here before $PATH
@@ -47,9 +47,9 @@ dnl input variables are set correctly.
 dnl CAUTION: Do not use this inside of a conditional.
 AC_DEFUN([BITCOIN_QT_INIT],[
   dnl enable qt support
-  AC_ARG_WITH([qt],
-    [AS_HELP_STRING([--with-qt],
-    [with qt (no|qt4|qt5|auto. default is auto, qt4 tried first.)])],
+  AC_ARG_WITH([gui],
+    [AS_HELP_STRING([--with-gui],
+    [with GUI (no|qt4|qt5|auto. default is auto, qt4 tried first.)])],
     [
      bitcoin_qt_want_version=$withval
      if test x$bitcoin_qt_want_version = xyes; then
@@ -59,10 +59,10 @@ AC_DEFUN([BITCOIN_QT_INIT],[
     ],
     [bitcoin_qt_want_version=auto])
 
-  AC_ARG_WITH([qt-incdir],[AS_HELP_STRING([--with-qt-incdir=INC_DIR],[specify qt include path (overridden by pkgconfig)])], [qt_include_path=$withval], [])
-  AC_ARG_WITH([qt-libdir],[AS_HELP_STRING([--with-qt-libdir=LIB_DIR],[specify qt lib path (overridden by pkgconfig)])], [qt_lib_path=$withval], [])
-  AC_ARG_WITH([qt-plugindir],[AS_HELP_STRING([--with-qt-plugindir=PLUGIN_DIR],[specify qt plugin path (overridden by pkgconfig)])], [qt_plugin_path=$withval], [])
-  AC_ARG_WITH([qt-bindir],[AS_HELP_STRING([--with-qt-bindir=BIN_DIR],[specify qt bin path])], [qt_bin_path=$withval], [])
+  AC_ARG_WITH([qt-incdir],[AS_HELP_STRING([--with-gui-incdir=INC_DIR],[specify qt include path (overridden by pkgconfig)])], [qt_include_path=$withval], [])
+  AC_ARG_WITH([qt-libdir],[AS_HELP_STRING([--with-gui-libdir=LIB_DIR],[specify qt lib path (overridden by pkgconfig)])], [qt_lib_path=$withval], [])
+  AC_ARG_WITH([qt-plugindir],[AS_HELP_STRING([--with-gui-plugindir=PLUGIN_DIR],[specify qt plugin path (overridden by pkgconfig)])], [qt_plugin_path=$withval], [])
+  AC_ARG_WITH([qt-bindir],[AS_HELP_STRING([--with-gui-bindir=BIN_DIR],[specify qt bin path])], [qt_bin_path=$withval], [])
 
   AC_ARG_WITH([qtdbus],
     [AS_HELP_STRING([--with-qtdbus],
@@ -73,7 +73,7 @@ AC_DEFUN([BITCOIN_QT_INIT],[
 
 dnl Find the appropriate version of Qt libraries and includes.
 dnl Inputs: $1: Whether or not pkg-config should be used. yes|no. Default: yes.
-dnl Inputs: $2: If $1 is "yes" and --with-qt=auto, which qt version should be
+dnl Inputs: $2: If $1 is "yes" and --with-gui=auto, which qt version should be
 dnl         tried first.
 dnl Outputs: See _BITCOIN_QT_FIND_LIBS_*
 dnl Outputs: Sets variables for all qt-related tools.
@@ -113,7 +113,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
 
 
   dnl enable qt support
-  AC_MSG_CHECKING(if QT should be enabled)
+  AC_MSG_CHECKING(whether to build Bitcoin Core GUI)
   BITCOIN_QT_CHECK([
     bitcoin_enable_qt=yes
     bitcoin_enable_qt_test=yes
@@ -149,11 +149,11 @@ dnl All macros below are internal and should _not_ be used from the main
 dnl configure.ac.
 dnl ----
 
-dnl Internal. Check if the included version of QT is Qt5.
+dnl Internal. Check if the included version of Qt is Qt5.
 dnl Requires: INCLUDES must be populated as necessary.
 dnl Output: bitcoin_cv_qt5=yes|no
 AC_DEFUN([_BITCOIN_QT_CHECK_QT5],[
-  AC_CACHE_CHECK(for QT 5, bitcoin_cv_qt5,[
+  AC_CACHE_CHECK(for Qt 5, bitcoin_cv_qt5,[
   AC_TRY_COMPILE(
     [#include <QtCore>],
     [
@@ -167,13 +167,13 @@ AC_DEFUN([_BITCOIN_QT_CHECK_QT5],[
     bitcoin_cv_qt5=no)
 ])])
 
-dnl Internal. Check if the linked version of QT was built as static libs.
+dnl Internal. Check if the linked version of Qt was built as static libs.
 dnl Requires: Qt5. This check cannot determine if Qt4 is static.
 dnl Requires: INCLUDES and LIBS must be populated as necessary.
 dnl Output: bitcoin_cv_static_qt=yes|no
 dnl Output: Defines QT_STATICPLUGIN if plugins are static.
 AC_DEFUN([_BITCOIN_QT_IS_STATIC],[
-  AC_CACHE_CHECK(for static QT, bitcoin_cv_static_qt,[
+  AC_CACHE_CHECK(for static Qt, bitcoin_cv_static_qt,[
   AC_TRY_COMPILE(
     [#include <QtCore>],
     [
@@ -187,7 +187,7 @@ AC_DEFUN([_BITCOIN_QT_IS_STATIC],[
     [bitcoin_cv_static_qt=no])
   ])
   if test xbitcoin_cv_static_qt = xyes; then
-    AC_DEFINE(QT_STATICPLUGIN, 1, [Define this symbol for static QT plugins])
+    AC_DEFINE(QT_STATICPLUGIN, 1, [Define this symbol for static Qt plugins])
   fi
 ])
 
@@ -197,7 +197,7 @@ dnl Inputs: $1: A series of Q_IMPORT_PLUGIN().
 dnl Inputs: $2: The libraries that resolve $1.
 dnl Output: QT_LIBS is prepended or configure exits.
 AC_DEFUN([_BITCOIN_QT_CHECK_STATIC_PLUGINS],[
-  AC_MSG_CHECKING(for static QT plugins: $2)
+  AC_MSG_CHECKING(for static Qt plugins: $2)
   CHECK_STATIC_PLUGINS_TEMP_LIBS="$LIBS"
   LIBS="$2 $QT_LIBS $LIBS"
   AC_TRY_LINK([
@@ -211,7 +211,7 @@ AC_DEFUN([_BITCOIN_QT_CHECK_STATIC_PLUGINS],[
 ])
 
 dnl Internal. Find Qt libraries using pkg-config.
-dnl Inputs: bitcoin_qt_want_version (from --with-qt=). The version to check
+dnl Inputs: bitcoin_qt_want_version (from --with-gui=). The version to check
 dnl         first.
 dnl Inputs: $1: If bitcoin_qt_want_version is "auto", check for this version
 dnl         first.
@@ -265,7 +265,7 @@ AC_DEFUN([_BITCOIN_QT_FIND_LIBS_WITH_PKGCONFIG],[
 
 dnl Internal. Find Qt libraries without using pkg-config. Version is deduced
 dnl from the discovered headers.
-dnl Inputs: bitcoin_qt_want_version (from --with-qt=). The version to use.
+dnl Inputs: bitcoin_qt_want_version (from --with-gui=). The version to use.
 dnl         If "auto", the version will be discovered by _BITCOIN_QT_CHECK_QT5.
 dnl Outputs: All necessary QT_* variables are set.
 dnl Outputs: bitcoin_qt_got_major_vers is set to "4" or "5".