[PATCH] Preprocessor: improve ACLE 6.4 support

[Saleem Abdulrasool]

Actually, the current handling of 6.4.2 is incorrect.  It is *supposed* to be a quoted char.  If you look at the example provided in 6.4.10, you will notice that this:

    #if __ARCH_ARM_PROFILE == 'R'

Fixed that as well.  That was a great catch!

http://reviews.llvm.org/D4146