rfc and [patch]: Unify -mfpu and .fpu handling, let .fpu toggle features

[Rafael Espíndola]

>> What is the size impact in libclang? It links with lib/Driver, no?
>
>
> From what I can tell looking at tools/clang/tools/libclang/CMakeLists.txt,
> it doesn't.

There is probably some indirect dependency. With a shared build I get:

ldd lib/libclang.so | grep -i driver
libclangDriver.so =>
/home/espindola/llvm/build/lib/../lib/libclangDriver.so
(0x00007f50f0e0c000)


Cheers,
Rafael