[Mesa-dev] Two last tiny fixes for preprocessor conformance

[Carl Worth]

So these last two, (very self-explanatory), patches complete my series based
on an initial pass over preprocessor-related failures I saw in the Khronos
GLES3 CTS.

There is at least one more failure caused by a test case that has a non-ASCII
character (decimal 129) in the name given to a #extension directive. I've
verified that glcpp itself passes that non-ASCII character through just fine,
so I'm assuming that the subsequent compiler chokes on it, but I haven't
chased that down just yet.

-Carl