The Android NDK would be moving to Clang as its default compiler
in the future. This patch allows OpenCV to build with the default
c++_shared / c++_static
TEST=Builds OpenCV with -DANDROID_TOOLCHAIN_NAME=
aarch64-linux-android-clang3.6 -DANDROID_STL=c++_shared
Add Android HardFP support. Expose the "armeabi-v7a-hard with NEON"
ANDROID_ABI.
TEST= Add -DANDROID_NATIVE_API_LEVEL=21
-DANDROID_ABI="armeabi-v7a-hard with NEON"
to compile with hardfp. Checked the output of make verbose to
confirm -lm_hard is being linked. There are known test
failures but that can be fixed once this is in.
