Merge #17227: Qt: Add Android packaging support

246774e26459cb3652e308880abdd140e8e9d204 depends: fix Qt precompiled headers bug (Igor Cota)
8e7ad4146d55f472e3d1dacaabb6b7dee704a896 depends: disable Qt Vulkan support on Android (Igor Cota)
ba46adaa1abd51798394b5bad3799021adc237d2 CI: add Android APK build to cirrus (Igor Cota)
7563720e30a3052b7ee390f1b3d2874856fd073a CI: add Android APK build script (Igor Cota)
ebfb10cb75adb704418d08197681c1e742e63bd5 Qt: add Android packaging support (Igor Cota)

Pull request description:

  ![bitcoin-qt](https://user-images.githubusercontent.com/762502/67396157-62f3d000-f5a7-11e9-8a6f-9425823fcd6c.gif)
  This PR is the third and final piece of the basic Android support puzzle - it depends on https://github.com/bitcoin/bitcoin/pull/16110 and is related to https://github.com/bitcoin/bitcoin/pull/16883. It introduces an `android` directory under `qt` and a simple way to build an Android package of `bitcoin-qt`:

  1. Build depends for Android as described in the [README](https://github.com/bitcoin/bitcoin/blob/master/depends/README.md)
  2. Configure with one of the resulting prefixes
  3. Run `make && make apk` in `src/qt`

  The resulting APK files will be in `android/build/outputs/apk`. You can install them manually or with [adb](https://developer.android.com/studio/command-line/adb). One can also open the `android` directory in Android Studio for that integrated development and debugging experience. `BitcoinQtActivity` is your starting point.

  Under the hood makefile `apk` target:

  1. Renames the `bitcoin-qt` binary to `libbitcoin-qt.so` and copies it over to a folder under `android/libs` depending on which prefix and corresponding [ABI](https://developer.android.com/ndk/guides/abis.html#sa) `bitcoin-qt` was built for
  2. Takes `libc++_shared.so` from the Android NDK and puts in the same place. It [must be included](https://developer.android.com/ndk/guides/cpp-support) in the APK
  3. Extracts Qt for Android Java support files from the `qtbase` archive in `depends/sources` to `android/src`

  There is also just a tiny bit of `ifdef`'d code to make the Qt Widgets menus usable. It's not pretty but it works and is a stepping stone towards https://github.com/bitcoin/bitcoin/pull/16883.

ACKs for top commit:
  MarcoFalke:
    cr ACK 246774e264
  laanwj:
    Code review ACK 246774e26459cb3652e308880abdd140e8e9d204

Tree-SHA512: ba30a746576a167545223c35a51ae60bb0838818779fc152c210f5af1413961b2a6ab6af520ff92cbc8dcd5dcb663e81ca960f021218430c1f76397ed4cead6c

1 files changed, 16 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 6815cefdbb..3de60cd6d4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -734,6 +734,21 @@ case $host in
    *android*)
      dnl make sure android stays above linux for hosts like *linux-android*
      TARGET_OS=android
+     case $host in
+       *x86_64*)
+          ANDROID_ARCH=x86_64
+          ;;
+        *aarch64*)
+          ANDROID_ARCH=arm64-v8a
+          ;;
+        *armv7a*)
+          ANDROID_ARCH=armeabi-v7a
+          ;;
+        *i686*)
+          ANDROID_ARCH=i686
+          ;;
+        *) AC_MSG_ERROR("Could not determine Android arch") ;;
+      esac
      ;;
    *linux*)
      TARGET_OS=linux
@@ -1849,6 +1864,7 @@ AC_SUBST(HAVE_BUILTIN_PREFETCH)
 AC_SUBST(HAVE_MM_PREFETCH)
 AC_SUBST(HAVE_STRONG_GETAUXVAL)
 AC_SUBST(HAVE_WEAK_GETAUXVAL)
+AC_SUBST(ANDROID_ARCH)
 AC_CONFIG_FILES([Makefile src/Makefile doc/man/Makefile share/setup.nsi share/qt/Info.plist test/config.ini])
 AC_CONFIG_FILES([contrib/devtools/split-debug.sh],[chmod +x contrib/devtools/split-debug.sh])
 AM_COND_IF([HAVE_DOXYGEN], [AC_CONFIG_FILES([doc/Doxyfile])])