build android native libraries

.github/workflows/build.yml

@@ -20,6 +20,50 @@ jobs:
           echo "version=$(sed -n 's/.*<TargetRaylibTag>\(.*\)<\/TargetRaylibTag>.*/\1/p' Raylib-cs/Raylib-cs.csproj)">> ${GITHUB_OUTPUT}
           echo "pkgversion=$(sed -n 's/.*<PackageVersion>\(.*\)<\/PackageVersion>.*/\1/p' Raylib-cs/Raylib-cs.csproj)">> ${GITHUB_OUTPUT}
 
+  build-android:
+    runs-on: ubuntu-latest
+    needs: prepare
+    strategy:
+      matrix:
+        name: [arm, arm64, x86, x64]
+        include:
+          - name: arm
+            arch: armeabi-v7a
+          - name: arm64
+            arch: arm64-v8a
+          - name: x86
+            arch: x86
+          - name: x64
+            arch: x86_64
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@v3
+
+      - name: build raylib
+        env:
+          version: ${{ needs.prepare.outputs.version }}
+        run: |
+          curl -Lso raylib.zip https://github.com/raysan5/raylib/archive/refs/tags/${version}.zip
+          unzip -qq raylib.zip
+          pushd raylib-${version}; patch -p1 < ../android.patch; popd
+          cmake -S raylib-${version} \
+            -B build \
+            -D CMAKE_BUILD_TYPE=Release \
+            -D BUILD_SHARED_LIBS=ON \
+            -D BUILD_EXAMPLES=OFF \
+            -D CMAKE_TOOLCHAIN_FILE=${ANDROID_NDK}/build/cmake/android.toolchain.cmake \
+            -D PLATFORM=Android \
+            -D ANDROID_ABI=${{ matrix.arch }}
+          cmake --build build --config Release
+          file build/raylib/libraylib.so # TODO: remove me
+
+      - name: upload build
+        uses: actions/upload-artifact@v3
+        with:
+          name: android-${{ matrix.name }}
+          path: build/raylib/libraylib.so
+          if-no-files-found: error
+
   build-linux:
     runs-on: ubuntu-latest
     needs: prepare
@@ -130,6 +174,7 @@ jobs:
     runs-on: ubuntu-latest
     needs:
       - prepare
+      - build-android
       - build-linux
       - build-osx
       - build-windows
@@ -137,6 +182,26 @@ jobs:
       - name: checkout repository
         uses: actions/checkout@v3
 
+      - uses: actions/download-artifact@v3
+        with:
+          name: android-arm
+          path: Raylib-cs/runtimes/android-arm/native
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: android-arm64
+          path: Raylib-cs/runtimes/android-arm64/native
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: android-x86
+          path: Raylib-cs/runtimes/android-x86/native
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: android-x64
+          path: Raylib-cs/runtimes/android-x64/native
+
       - uses: actions/download-artifact@v3
         with:
           name: linux-x64

android.patch

@@ -0,0 +1,24 @@
+diff --git a/src/rcore.c b/src/rcore.c
+index eae4951..76e26ad 100644
+--- a/src/rcore.c
++++ b/src/rcore.c
+@@ -709,7 +709,18 @@ const char *TextFormat(const char *text, ...);       // Formatting of text with
+ #if defined(PLATFORM_ANDROID)
+ // To allow easier porting to android, we allow the user to define a
+ // main function which we call from android_main, defined by ourselves
+-extern int main(int argc, char *argv[]);
++
++typedef void (*RaylibAndroidCallback)();
++static RaylibAndroidCallback _androidCallback = NULL;
++
++void RaylibSetAndroidCallback(RaylibAndroidCallback callback) {
++    _androidCallback = callback;
++}
++
++int main(int argc, char *argv[]) {
++    while(_androidCallback == NULL) {}
++    _androidCallback();
++}
+ 
+ void android_main(struct android_app *app)
+ {