https://android.googlesource.com/platform/ndk/+/master/docs/...
<quote>
Remove GCC
GCC is still in the NDK today because some of gnustl's C++11 features were written such that they do not work with Clang (threading and atomics, mostly). Now that libc++ is the best choice of STL, this is no longer blocking, so GCC can be removed.
</quote>
https://android.googlesource.com/platform/ndk/+/master/docs/...
<quote>
Remove GCC
GCC is still in the NDK today because some of gnustl's C++11 features were written such that they do not work with Clang (threading and atomics, mostly). Now that libc++ is the best choice of STL, this is no longer blocking, so GCC can be removed.
</quote>