From the Android NDK Changelog for NDK Build 2490520:
PSA: Everyone should be switching to Clang.
Clang has been updated to 3.8svn (r243773, build 2481030).
Note that this is now a nearly pure upstream clang.
Also note that Clang packaged in the Windows 64 NDK is actually 32-bit.
Support for emulated TLS.
__thread is now supported by the compiler by emulating ELF TLS with pthread thread-specific data.
C++11 thread_local will work in some cases, but will not work for data with non-trivial destructors except when running on Marshmallow (android-23) or newer because those cases require support from libc.
Does not yet work with Aarch64 when TLS variables are accessed from a shared library.
GCC in the NDK is now deprecated.
Time to start using Clang if you haven’t already. If you have problems with Clang, please file bugs!
The NDK will not be upgrading to 5.x, nor will we be accepting non-critical backports.
Maintenance for miscompiles and internal compiler errors in 4.9 will be handled on a case by case basis.
GCC 4.8 has been removed. All targets now use GCC 4.9.