Attached is a fifth revision (963a2cce068d.diff) of my patch.

I was trying to avoid submitting any more revisions if possible, since this I think this patch is essentially feature-complete. However, this revision adds two things which I felt were needed:

* This patch fixes a serious oversight where UnixCCompiler.get_compiler_version() wouldn't correctly handle compiler names which contains an absolute file path, or suffixes such as ".exe" (which could happen under mingw). This corrects for that, and adds tests for those cases. 

* After thinking about it, I realized the "--get-compiler-info" option I mentioned in my last post was in fact sorely needed... otherwise there is no easy way for users to determine what string specific_compile_args is using to match against its regexp patterns; such as in Roumen's question. (I hope I wasn't overstepping any bounds by going ahead and implementing this)

The option can be run via "pysetup3 -q run build_ext --get-compiler-info". Instead of compiling any extensions, it causes build_ext to print out two lines: the first containing the name of the active compiler class, and the second containing the exact string that will be matched by specific_compile_args. I've added references to this in the documentation, as well as unittests to make sure it behaves properly.