ci: add meson android aarch64 build

Passing -Wno-pointer-bool-conversion in cross file
to suppress compiler warning:

src/fcfreetype.c:1373:11: address of array 'os2->achVendID' will always evaluate to 'true'

.gitlab-ci.yml

@@ -225,3 +225,46 @@ meson msys2:
     - C:\msys64\usr\bin\bash -c "meson build $env:MESON_ARGS &&
         ninja -C build &&
         ninja -C build test"
+
+meson android arm64 fedora:
+  # See https://gitlab.freedesktop.org/gstreamer/gst-ci/container_registry/164 for current images
+  image: 'registry.freedesktop.org/gstreamer/gst-ci/amd64/android-fedora:2020-10-22.0-master'
+  stage: 'build'
+  artifacts:
+    name: "${CI_JOB_NAME}_${CI_COMMIT_SHA}"
+    expire_in: '5 days'
+    when: 'always'
+    paths:
+      - "build/meson-logs/*.txt"
+  before_script:
+    - dnf install -y python3-pip gcc ninja-build gperf
+    - pip3 install --user meson
+  script:
+    - export PATH="$HOME/.local/bin:$PATH"
+    - |
+      cat > android-cross-file.txt <<EOF
+      [constants]
+      ndk_path    = '/android/ndk'
+      toolchain   = ndk_path + '/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android'
+      api         = '28'
+
+      [host_machine]
+      system      = 'android'
+      cpu_family  = 'aarch64'
+      cpu         = 'aarch64'
+      endian      = 'little'
+
+      [properties]
+      sys_root        = ndk_path + '/sysroot'
+      c_args          = ['-Wno-pointer-bool-conversion']
+      c_link_args     = ['-fuse-ld=gold']
+      cpp_link_args   = ['-fuse-ld=gold']
+
+      [binaries]
+      c           = toolchain + api + '-clang'
+      cpp         = toolchain + api + '-clang++'
+      ar          = toolchain + '-ar'
+      strip       = toolchain + '-strip'
+      EOF
+    - meson setup --werror --cross-file android-cross-file.txt build
+    - meson compile --verbose -C build