It should be possible to tweak distutils to do the right thing for 
upcoming releases, distutils already contains some special code to allow 
building extensions for a univeral build on 10.3.9 (where the compiler 
doesn't support universal builds at all) and we could extend that for 
the compiler version on SL.

Implementation sketch:
* Record the compiler version during build (using configure)
* Store the compiler version as a variable in Makefile.pre.in
* Teach distutils to read that variable and adjust the compiler 
  path ($CC,$LD,...)

This bit would only be active on OSX.