Merging r143871:
------------------------------------------------------------------------
r143871 | chandlerc | 2011-11-06 01:39:46 -0800 (Sun, 06 Nov 2011) | 3 lines
Lift the GCCVersion type into the header file and start persisting it in
the detected GCC installation. This allows us to expose another aspect
of what we detected: the GCC version. This will be used shortly.
------------------------------------------------------------------------
llvm-svn: 143948
