prefer the toolchain file bundled with android ndk

build.sh

@@ -3,7 +3,7 @@
 ##### android armv7
 mkdir -p build-android-armv7
 pushd build-android-armv7
-cmake -DCMAKE_TOOLCHAIN_FILE=../android.toolchain.cmake -DANDROID_ABI="armeabi-v7a with NEON" -DANDROID_NATIVE_API_LEVEL=android-9 -DANDROID_FORCE_ARM_BUILD=OFF -DANDROID_STL_FORCE_FEATURES=OFF ..
+cmake -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake -DANDROID_ABI="armeabi-v7a" -DANDROID_ARM_NEON=ON -DANDROID_PLATFORM=android-14 ..
 make
 make install
 popd
@@ -11,7 +11,7 @@ popd
 ##### android aarch64
 mkdir -p build-android-aarch64
 pushd build-android-aarch64
-cmake -DCMAKE_TOOLCHAIN_FILE=../android.toolchain.cmake -DANDROID_ABI="arm64-v8a" -DANDROID_NATIVE_API_LEVEL=android-21 -DANDROID_FORCE_ARM_BUILD=OFF -DANDROID_STL_FORCE_FEATURES=OFF ..
+cmake -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake -DANDROID_ABI="arm64-v8a" -DANDROID_PLATFORM=android-21 ..
 make
 make install
 popd
@@ -19,7 +19,7 @@ popd
 ##### android armv7 without neon
 mkdir -p build-android-armv7-without-neon
 pushd build-android-armv7-without-neon
-cmake -DCMAKE_TOOLCHAIN_FILE=../android.toolchain.cmake -DANDROID_ABI="armeabi-v7a" -DANDROID_NATIVE_API_LEVEL=android-9 -DANDROID_FORCE_ARM_BUILD=OFF -DANDROID_STL_FORCE_FEATURES=OFF ..
+cmake -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake -DANDROID_ABI="armeabi-v7a" -DANDROID_PLATFORM=android-14 ..
 make
 make install
 popd
@@ -49,4 +49,4 @@ cmake   -DNCNN_OPENMP=OFF \
         ..
 make -j 8
 make install
-popd
+popd