Backport mkmf changes?
This was committed by Aaron Patterson in revision (r29842). It relates to the issue I submitted here:
I included the patch there, for 1.9.2. The change is very simple. It removes the hardcoding within mkmf, away from "gcc for .c" and "g++ for CXX_EXT". With the patch, gcc compiles against what you have in "SRC_EXT".