[PATCH] Preprocessor: improve ACLE 6.4 support

[Tim Northover]

>> A quick GCC test suggests this is how they do it ("#define __ARM_ARCH_PROFILE 65" for Cortex-A15, which is also dodgy in C++ mode, but less so).
> I'd prefer a quoted char.

Me too. From the ACLE wording, I'd expect sizeof(__ARM_ARCH_PROFILE)
== 1 in C++ mode.

Cheers.

Tim.