action: add Android build test

Android is the major release target of nntrainer.
Build and run test cases for Android.

Signed-off-by: MyungJoo Ham <[email protected]>

.github/workflows/android.yml

@@ -0,0 +1,61 @@
+name: Build test/ Android NDK
+
+on:
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    name: Android NDK build on Ubuntu for arm64-v8a
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
+        fetch-depth: -${{ github.event.pull_request.commits }}
+    - name: Check if rebuild required
+      uses: ./.github/actions/check-rebuild
+      with:
+        mode: android
+    - if: env.rebuild == '1'
+      uses: nttld/setup-ndk@v1
+      with:
+        ndk-version: r26d
+        link-to-sdk: true
+    ## @todo Make cache works (daily update cache on main branch / restore the cache on each PR (w/o saving))
+    - name: Prepare Build
+      if: env.rebuild == '1'
+      run: |
+        echo "::group::Install required packages"
+        sudo apt-get update
+        sudo apt-get install tar wget gzip libglib2.0-dev libjson-glib-dev libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev libunwind-dev googletest liborc-0.4-dev flex bison libopencv-dev pkg-config python3-dev python3-numpy python3 meson ninja-build libflatbuffers-dev flatbuffers-compiler protobuf-compiler
+        echo "::endgroup::"
+    - name: NDK Build
+      if: env.rebuild == '1'
+      run: |
+        echo "::group::Run package_android.sh"
+        ./tools/package_android.sh
+        echo "::endgroup::"
+        echo "::group::Meson build"
+        meson build -Dplatform=android
+        ninja -C build
+        echo "::endgroup::"
+        echo "::group::NDK build"
+        pushd build/jni
+        ndk-build NDK_PROJECT_PATH=./ APP_BUILD_SCRIPT=./Android.mk NDK_APPLICATION_MK=./Application.mk
+        popd
+        echo "::endgroup::"
+    - name: Install built binaries for application build
+      if: env.rebuild == '1'
+      run: |
+        echo "Installing build bianries for application build"
+        mkdir -p libs/arm64-v8a
+        cp -R build/jni/libs/arm64-v8a/* libs/arm64-v8a
+    - name: Android NNTrainer Application Build
+      if: env.rebuild == '1'
+      run: |
+        echo "::group::LogisticRegression"
+        pushd Applications/LogisticRegression/jni
+        ndk-build NDK_PROJECT_PATH=./ APP_BUILD_SCRIPT=./Android.mk NDK_APPLICATION_MK=./Application.mk
+        popd
+        echo "::endgroup::"