Use Clang & libc++
See the commit message for the rationale.
The main motivation is to support android-platform-libart
. libart
contains assembly code that can't be compiled by GCC but Clang, and Clang is not happy with libstdc++
.
After the changes to this package, all other Android packages that uses any C++ libraries in here must switch to Clang and libc++
as well.