14 files changed, 188 insertions, 5 deletions
diff --git a/depends/Makefile b/depends/Makefile
index 80df0e46f8..cec99777ff 100644
--- a/depends/Makefile
+++ b/depends/Makefile
@@ -58,6 +58,11 @@ full_host_os:=$(subst $(host_arch)-$(host_vendor)-,,$(canonical_host))
 host_os:=$(findstring linux,$(full_host_os))
 host_os+=$(findstring darwin,$(full_host_os))
 host_os+=$(findstring mingw32,$(full_host_os))
+
+ifeq (android,$(findstring android,$(full_host_os)))
+host_os:=android
+endif
+
 host_os:=$(strip $(host_os))
 ifeq ($(host_os),)
 host_os=$(full_host_os)
diff --git a/depends/README.md b/depends/README.md
index ca542be13f..e5e2a8a653 100644
--- a/depends/README.md
+++ b/depends/README.md
@@ -30,8 +30,12 @@ Common `host-platform-triplets` for cross compilation are:
 - `aarch64-linux-gnu` for Linux ARM 64 bit
 - `riscv32-linux-gnu` for Linux RISC-V 32 bit
 - `riscv64-linux-gnu` for Linux RISC-V 64 bit
+- `armv7a-linux-android` for Android ARM 32 bit
+- `aarch64-linux-android` for Android ARM 64 bit
+- `i686-linux-android` for Android x86 32 bit
+- `x86_64-linux-android` for Android x86 64 bit
 
-No other options are needed, the paths are automatically configured.
+The paths are automatically configured and no other options are needed unless targeting [Android](#Android).
 
 ### Install the required dependencies: Ubuntu & Debian
 
@@ -90,6 +94,19 @@ options will be passed to bitcoin's configure. In this case, `--disable-wallet`.
     download-win: run 'make download-win' to fetch all sources needed for win builds
     download-linux: run 'make download-linux' to fetch all sources needed for linux builds
 
+
+### Android
+
+Before proceeding with an Android build one needs to get the [Android SDK](https://developer.android.com/studio) and use the "SDK Manager" tool to download the NDK and one or more "Platform packages" (these are Android versions and have a corresponding API level).
+In order to build `ANDROID_API_LEVEL` (API level corresponding to the Android version targeted, e.g. Android 9.0 Pie is 28 and its "Platform package" needs to be available) and `ANDROID_TOOLCHAIN_BIN` (path to toolchain binaries depending on the platform the build is being performed on) need to be set.
+
+API levels from 24 to 29 have been tested to work.
+
+If the build includes Qt, environment variables `ANDROID_SDK` and `ANDROID_NDK` need to be set as well but can otherwise be omitted.
+This is an example command for a default build with no disabled dependencies:
+
+    ANDROID_SDK=/home/user/Android/Sdk ANDROID_NDK=/home/user/Android/Sdk/ndk-bundle make HOST=aarch64-linux-android ANDROID_API_LEVEL=28 ANDROID_TOOLCHAIN_BIN=/home/user/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/linux-x86_64/bin
+
 ### Other documentation
 
 - [description.md](description.md): General description of the depends system
diff --git a/depends/hosts/android.mk b/depends/hosts/android.mk
new file mode 100644
index 0000000000..969ec2a1cb
--- /dev/null
+++ b/depends/hosts/android.mk
@@ -0,0 +1,11 @@
+ifeq ($(HOST),armv7a-linux-android)
+android_AR=$(ANDROID_TOOLCHAIN_BIN)/arm-linux-androideabi-ar
+android_CXX=$(ANDROID_TOOLCHAIN_BIN)/$(HOST)eabi$(ANDROID_API_LEVEL)-clang++
+android_CC=$(ANDROID_TOOLCHAIN_BIN)/$(HOST)eabi$(ANDROID_API_LEVEL)-clang
+android_RANLIB=$(ANDROID_TOOLCHAIN_BIN)/arm-linux-androideabi-ranlib
+else
+android_AR=$(ANDROID_TOOLCHAIN_BIN)/$(HOST)-ar
+android_CXX=$(ANDROID_TOOLCHAIN_BIN)/$(HOST)$(ANDROID_API_LEVEL)-clang++
+android_CC=$(ANDROID_TOOLCHAIN_BIN)/$(HOST)$(ANDROID_API_LEVEL)-clang
+android_RANLIB=$(ANDROID_TOOLCHAIN_BIN)/$(HOST)-ranlib
+endif
diff --git a/depends/packages/boost.mk b/depends/packages/boost.mk
index 766b8d224e..d360bb5ba6 100644
--- a/depends/packages/boost.mk
+++ b/depends/packages/boost.mk
@@ -15,12 +15,17 @@ $(package)_config_opts_mingw32=binary-format=pe target-os=windows threadapi=win3
 $(package)_config_opts_x86_64_mingw32=address-model=64
 $(package)_config_opts_i686_mingw32=address-model=32
 $(package)_config_opts_i686_linux=address-model=32 architecture=x86
+$(package)_config_opts_i686_android=address-model=32
+$(package)_config_opts_aarch64_android=address-model=64
+$(package)_config_opts_x86_64_android=address-model=64
+$(package)_config_opts_armv7a_android=address-model=32
 $(package)_toolset_$(host_os)=gcc
 $(package)_archiver_$(host_os)=$($(package)_ar)
 $(package)_toolset_darwin=clang-darwin
 $(package)_config_libraries=chrono,filesystem,system,thread,test
 $(package)_cxxflags=-std=c++11 -fvisibility=hidden
 $(package)_cxxflags_linux=-fPIC
+$(package)_cxxflags_android=-fPIC
 endef
 
 define $(package)_preprocess_cmds
diff --git a/depends/packages/libevent.mk b/depends/packages/libevent.mk
index 300c806a8d..b4333abaf0 100644
--- a/depends/packages/libevent.mk
+++ b/depends/packages/libevent.mk
@@ -3,16 +3,24 @@ $(package)_version=2.1.8-stable
 $(package)_download_path=https://github.com/libevent/libevent/archive/
 $(package)_file_name=release-$($(package)_version).tar.gz
 $(package)_sha256_hash=316ddb401745ac5d222d7c529ef1eada12f58f6376a66c1118eee803cb70f83d
+$(package)_patches=fix_android_arc4random_addrandom.patch
 
-define $(package)_preprocess_cmds
-  ./autogen.sh
-endef
+ifneq (,$(findstring android,$(host)))
+  define $(package)_preprocess_cmds
+    ./autogen.sh && patch -p1 < $($(package)_patch_dir)/fix_android_arc4random_addrandom.patch
+  endef
+else
+  define $(package)_preprocess_cmds
+    ./autogen.sh
+  endef
+endif
 
 define $(package)_set_vars
   $(package)_config_opts=--disable-shared --disable-openssl --disable-libevent-regress --disable-samples
   $(package)_config_opts += --disable-dependency-tracking --enable-option-checking
   $(package)_config_opts_release=--disable-debug-mode
   $(package)_config_opts_linux=--with-pic
+  $(package)_config_opts_android=--with-pic
 endef
 
 define $(package)_config_cmds
diff --git a/depends/packages/openssl.mk b/depends/packages/openssl.mk
index 3498a3f6ee..e3b3647dd9 100644
--- a/depends/packages/openssl.mk
+++ b/depends/packages/openssl.mk
@@ -58,6 +58,11 @@ $(package)_config_opts_riscv64_linux=linux-generic64
 $(package)_config_opts_x86_64_darwin=darwin64-x86_64-cc
 $(package)_config_opts_x86_64_mingw32=mingw64
 $(package)_config_opts_i686_mingw32=mingw
+$(package)_config_opts_android=-fPIC
+$(package)_config_opts_aarch64_android=linux-generic64
+$(package)_config_opts_x86_64_android=linux-generic64
+$(package)_config_opts_armv7a_android=linux-generic32
+$(package)_config_opts_i686_android=linux-generic32
 endef
 
 define $(package)_preprocess_cmds
diff --git a/depends/packages/packages.mk b/depends/packages/packages.mk
index 35f8b829db..09734c7e6f 100644
--- a/depends/packages/packages.mk
+++ b/depends/packages/packages.mk
@@ -3,6 +3,7 @@ packages:=boost openssl libevent
 qt_packages = qrencode zlib
 
 qt_linux_packages:=qt expat libxcb xcb_proto libXau xproto freetype fontconfig
+qt_android_packages=qt
 
 rapidcheck_packages = rapidcheck
 
diff --git a/depends/packages/qrencode.mk b/depends/packages/qrencode.mk
index 21570726ff..d1687883bc 100644
--- a/depends/packages/qrencode.mk
+++ b/depends/packages/qrencode.mk
@@ -9,6 +9,7 @@ $(package)_config_opts=--disable-shared --without-tools --without-tests --disabl
 $(package)_config_opts += --disable-gprof --disable-gcov --disable-mudflap
 $(package)_config_opts += --disable-dependency-tracking --enable-option-checking
 $(package)_config_opts_linux=--with-pic
+$(package)_config_opts_android=--with-pic
 endef
 
 define $(package)_preprocess_cmds
diff --git a/depends/packages/qt.mk b/depends/packages/qt.mk
index 0685eb2da2..a0f7cda2c0 100644
--- a/depends/packages/qt.mk
+++ b/depends/packages/qt.mk
@@ -8,7 +8,7 @@ $(package)_dependencies=zlib
 $(package)_linux_dependencies=freetype fontconfig libxcb
 $(package)_build_subdir=qtbase
 $(package)_qt_libs=corelib network widgets gui plugins testlib
-$(package)_patches=fix_qt_pkgconfig.patch mac-qmake.conf fix_configure_mac.patch fix_no_printer.patch fix_rcc_determinism.patch fix_riscv64_arch.patch xkb-default.patch no-xlib.patch
+$(package)_patches=fix_qt_pkgconfig.patch mac-qmake.conf fix_configure_mac.patch fix_no_printer.patch fix_rcc_determinism.patch fix_riscv64_arch.patch xkb-default.patch no-xlib.patch fix_android_qmake_conf.patch fix_android_jni_static.patch
 
 $(package)_qttranslations_file_name=qttranslations-$($(package)_suffix)
 $(package)_qttranslations_sha256_hash=fb5a47799754af73d3bf501fe513342cfe2fc37f64e80df5533f6110e804220c
@@ -128,6 +128,26 @@ $(package)_config_opts_x86_64_linux = -xplatform linux-g++-64
 $(package)_config_opts_aarch64_linux = -xplatform linux-aarch64-gnu-g++
 $(package)_config_opts_riscv64_linux = -platform linux-g++ -xplatform bitcoin-linux-g++
 $(package)_config_opts_mingw32  = -no-opengl -xplatform win32-g++ -device-option CROSS_COMPILE="$(host)-"
+
+$(package)_config_opts_android = -xplatform android-clang
+$(package)_config_opts_android += -android-sdk $(ANDROID_SDK)
+$(package)_config_opts_android += -android-ndk $(ANDROID_NDK)
+$(package)_config_opts_android += -android-ndk-platform android-$(ANDROID_API_LEVEL)
+$(package)_config_opts_android += -device-option CROSS_COMPILE="$(host)-"
+$(package)_config_opts_android += -egl
+$(package)_config_opts_android += -qpa xcb
+$(package)_config_opts_android += -no-eglfs
+$(package)_config_opts_android += -opengl es2
+$(package)_config_opts_android += -qt-freetype
+$(package)_config_opts_android += -no-fontconfig
+$(package)_config_opts_android += -L $(host_prefix)/lib
+$(package)_config_opts_android += -I $(host_prefix)/include
+
+$(package)_config_opts_aarch64_android += -android-arch arm64-v8a
+$(package)_config_opts_armv7a_android += -android-arch armeabi-v7a
+$(package)_config_opts_x86_64_android += -android-arch x86_64
+$(package)_config_opts_i686_android += -android-arch i686
+
 $(package)_build_env  = QT_RCC_TEST=1
 $(package)_build_env += QT_RCC_SOURCE_DATE_OVERRIDE=1
 endef
@@ -170,6 +190,8 @@ define $(package)_preprocess_cmds
   patch -p1 -i $($(package)_patch_dir)/fix_no_printer.patch &&\
   patch -p1 -i $($(package)_patch_dir)/fix_rcc_determinism.patch &&\
   patch -p1 -i $($(package)_patch_dir)/xkb-default.patch &&\
+  patch -p1 -i $($(package)_patch_dir)/fix_android_qmake_conf.patch &&\
+  patch -p1 -i $($(package)_patch_dir)/fix_android_jni_static.patch &&\
   echo "!host_build: QMAKE_CFLAGS     += $($(package)_cflags) $($(package)_cppflags)" >> qtbase/mkspecs/common/gcc-base.conf && \
   echo "!host_build: QMAKE_CXXFLAGS   += $($(package)_cxxflags) $($(package)_cppflags)" >> qtbase/mkspecs/common/gcc-base.conf && \
   echo "!host_build: QMAKE_LFLAGS     += $($(package)_ldflags)" >> qtbase/mkspecs/common/gcc-base.conf && \
diff --git a/depends/packages/zeromq.mk b/depends/packages/zeromq.mk
index ce85c437bb..6f35ede248 100644
--- a/depends/packages/zeromq.mk
+++ b/depends/packages/zeromq.mk
@@ -11,6 +11,7 @@ define $(package)_set_vars
   $(package)_config_opts += --disable-libunwind --disable-radix-tree --without-gcov --disable-dependency-tracking
   $(package)_config_opts += --disable-Werror --disable-drafts --enable-option-checking
   $(package)_config_opts_linux=--with-pic
+  $(package)_config_opts_android=--with-pic
   $(package)_cxxflags=-std=c++11
 endef
 
diff --git a/depends/packages/zlib.mk b/depends/packages/zlib.mk
index 168f85e65e..acb02020a8 100644
--- a/depends/packages/zlib.mk
+++ b/depends/packages/zlib.mk
@@ -11,6 +11,7 @@ $(package)_config_opts+=RANLIB="$($(package)_ranlib)"
 $(package)_config_opts+=AR="$($(package)_ar)"
 $(package)_config_opts_darwin+=AR="$($(package)_libtool)"
 $(package)_config_opts_darwin+=ARFLAGS="-o"
+$(package)_config_opts_android+=CHOST=$(host)
 endef
 
 # zlib has its own custom configure script that takes in options like CC,
diff --git a/depends/patches/libevent/fix_android_arc4random_addrandom.patch b/depends/patches/libevent/fix_android_arc4random_addrandom.patch
new file mode 100644
index 0000000000..5bcc64bef6
--- /dev/null
+++ b/depends/patches/libevent/fix_android_arc4random_addrandom.patch
@@ -0,0 +1,68 @@
+From cadae3ab7abf45e61ecae8aac39d97d1f3cbd336 Mon Sep 17 00:00:00 2001
+From: Lawrence Nahum <lawrence@greenaddress.it>
+Date: Sun, 3 Dec 2017 22:56:09 +0100
+Subject: [PATCH] fixup
+
+---
+ configure.ac          | 1 +
+ evutil_rand.c         | 3 +++
+ include/event2/util.h | 4 ++--
+ 3 files changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 7528d37..3bb2121 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -341,6 +341,7 @@ dnl Checks for library functions.
+ AC_CHECK_FUNCS([ \
+   accept4 \
+   arc4random \
++  arc4random_addrandom \
+   arc4random_buf \
+   eventfd \
+   epoll_create1 \
+diff --git a/evutil_rand.c b/evutil_rand.c
+index 046a14b..3f0bf2c 100644
+--- a/evutil_rand.c
++++ b/evutil_rand.c
+@@ -191,6 +191,7 @@ evutil_secure_rng_get_bytes(void *buf, size_t n)
+ {
+ 	ev_arc4random_buf(buf, n);
+ }
++#ifdef HAVE_ARC4RANDOM_ADDRANDOM
+ 
+ void
+ evutil_secure_rng_add_bytes(const char *buf, size_t n)
+@@ -199,6 +200,8 @@ evutil_secure_rng_add_bytes(const char *buf, size_t n)
+ 	    n>(size_t)INT_MAX ? INT_MAX : (int)n);
+ }
+ 
++#endif
++
+ void
+ evutil_free_secure_rng_globals_(void)
+ {
+diff --git a/include/event2/util.h b/include/event2/util.h
+index dd4bbb6..a9a169d 100644
+--- a/include/event2/util.h
++++ b/include/event2/util.h
+@@ -841,7 +841,7 @@ int evutil_secure_rng_init(void);
+  */
+ EVENT2_EXPORT_SYMBOL
+ int evutil_secure_rng_set_urandom_device_file(char *fname);
+-
++#ifdef HAVE_ARC4RANDOM_ADDRANDOM
+ /** Seed the random number generator with extra random bytes.
+ 
+     You should almost never need to call this function; it should be
+@@ -858,7 +858,7 @@ int evutil_secure_rng_set_urandom_device_file(char *fname);
+  */
+ EVENT2_EXPORT_SYMBOL
+ void evutil_secure_rng_add_bytes(const char *dat, size_t datlen);
+-
++#endif
+ #ifdef __cplusplus
+ }
+ #endif
+-- 
+2.14.3
diff --git a/depends/patches/qt/fix_android_jni_static.patch b/depends/patches/qt/fix_android_jni_static.patch
new file mode 100644
index 0000000000..2f6ff00f40
--- /dev/null
+++ b/depends/patches/qt/fix_android_jni_static.patch
@@ -0,0 +1,18 @@
+--- old/qtbase/src/plugins/platforms/android/androidjnimain.cpp
++++ new/qtbase/src/plugins/platforms/android/androidjnimain.cpp
+@@ -890,6 +890,14 @@
+         __android_log_print(ANDROID_LOG_FATAL, "Qt", "registerNatives failed");
+         return -1;
+     }
++
++    const jint ret = QT_PREPEND_NAMESPACE(QtAndroidPrivate::initJNI(vm, env));
++    if (ret != 0)
++    {
++        __android_log_print(ANDROID_LOG_FATAL, "Qt", "initJNI failed");
++        return ret;
++    }
++
+     QWindowSystemInterfacePrivate::TabletEvent::setPlatformSynthesizesMouse(false);
+ 
+     m_javaVM = vm;
+
diff --git a/depends/patches/qt/fix_android_qmake_conf.patch b/depends/patches/qt/fix_android_qmake_conf.patch
new file mode 100644
index 0000000000..13bfff9776
--- /dev/null
+++ b/depends/patches/qt/fix_android_qmake_conf.patch
@@ -0,0 +1,20 @@
+--- old/qtbase/mkspecs/android-clang/qmake.conf
++++ new/qtbase/mkspecs/android-clang/qmake.conf
+@@ -30,7 +30,7 @@
+     QMAKE_CFLAGS += -target mips64el-none-linux-android
+ 
+ QMAKE_CFLAGS += -gcc-toolchain $$NDK_TOOLCHAIN_PATH
+-QMAKE_LINK    = $$QMAKE_CXX $$QMAKE_CFLAGS -Wl,--exclude-libs,libgcc.a
++QMAKE_LINK    = $$QMAKE_CXX $$QMAKE_CFLAGS -Wl,--exclude-libs,libgcc.a -nostdlib++
+ QMAKE_CFLAGS += -DANDROID_HAS_WSTRING --sysroot=$$NDK_ROOT/sysroot \
+                 -isystem $$NDK_ROOT/sysroot/usr/include/$$NDK_TOOLS_PREFIX \
+                 -isystem $$NDK_ROOT/sources/cxx-stl/llvm-libc++/include \
+@@ -40,7 +40,7 @@
+ ANDROID_SOURCES_CXX_STL_LIBDIR = $$NDK_ROOT/sources/cxx-stl/llvm-libc++/libs/$$ANDROID_TARGET_ARCH
+ 
+ ANDROID_STDCPP_PATH = $$ANDROID_SOURCES_CXX_STL_LIBDIR/libc++_shared.so
+-ANDROID_CXX_STL_LIBS = -lc++
++ANDROID_CXX_STL_LIBS = -lc++_shared
+ 
+ QMAKE_ARM_CFLAGS_RELEASE                   = -Oz
+ QMAKE_ARM_CFLAGS_RELEASE_WITH_DEBUGINFO    = -g -Oz