namespace-invasive CPP built-ins

[Jason R Thorpe]

Hi Neil...

Sorry for the delay in bringing this up, but I have not had much time
for GCC stuff for the last ... too long.  Anway...

In May, you made a change to config/alpha/alpha.h to put the LANGUAGE_*
defines into TARGET_CPU_CPP_BUILTINS() ... I overlooked it at first, but
the LANGUAGE_* defines were recently brought to my attention by someone
else in the context of MIPS, and so I started looking around and noticed
them on Alpha, too.

The rub here is the "LANGUAGE_C" define ... it is namespace-invasive,
and some targets (like NetBSD) try to keep stuff like that out of the
namespace regardless of stdc options...

I guess it boils down to the fact that stuff like LANGUAGE_* is kind
of OS-specific .. no all OSs use it in their headers or source code,
and testing those defines certainly isn't portable in the general sense.

I'd like to figure out some way to sanely move these things out of
TARGET_CPU_CPP_BUILTINS() and into some other construct.  Thoughts?

-- 
        -- Jason R. Thorpe <thorpej@wasabisystems.com>