Add support for Ananas platform
Ananas is a home-brew operating system, mainly for amd64 machines. After
using GCC for quite some time, it has switched to clang and never looked
back - yet, having to manually patch things is annoying, so it'd be much
nicer if this was in the official tree.
Submitted by: Rink Springer
Differential Revision: https://reviews.llvm.org/D32937