Merge #16110: depends: Add Android NDK support

f9af3ced1c Android: add all arch support (Block Mechanic)
d419ca7e32 depends: export dynamic JNI symbols from static qtforandroid.a (Igor Cota)
ed30684d03 Qt: patch androidjnimain.cpp to make sure JNI is initialised when statically compiled (Igor Cota)
e4c319e8a1 builds: remove superfluous config_opts_aarch64_android (Igor Cota)
24ffef0c27 Patch libevent when building for Android (fix arc4random_addrandom) (Igor Cota)
f1e40b3e71 Update bitcoin_qt.m4 (BlockMechanic)
b4057d8261 Define TARGET_OS when host is android (Igor Cota)
80b475f159 Fix Android zlib cross compilation issue (https://stackoverflow.com/questions/21396988/zlib-build-not-configuring-properly-with-cross-compiler-ignores-ar) (Igor Cota)
45f8219015 Add full Android build example command and instructions on getting SDK/NDK (Igor Cota)
b68f2a68c2 Add config opts and patch for aarch64_android build of Qt (Igor Cota)
9c4cb0166e Add ranlib to android.mk hosts file (fix OSX Android NDK build) (Igor Cota)
c2a749c9c1 Add example Android host-platform-triplet and options (Igor Cota)
0b0cff3c61 Add support for building Android dependencies (Igor Cota)

Pull request description:

  This allows one to build the dependencies with the Android SDK and goes towards fixing #11844. It has been tested to work with:
  `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 NO_QT=1 NO_WALLET=1`

ACKs for top commit:
  Sjors:
    ACK f9af3ce. I'm OK with merging and then improving later.

Tree-SHA512: cb805115ebe5c9e33db2bf3eab8628808fe3f50052053d8877d8b8e4406d6fea1ed9e5c4dff85d777fb99c81be6ffb9d95a0e6d32344e728e5e0da6c653e2ce7

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 && \