With homebrew it's feasible if not quite completely painless. When Lion came out, I had problems with some C extensions that expect gcc, but found llvm-gcc or

With homebrew it's feasible if not quite completely painless. When Lion came out, I had problems with some C extensions that expect gcc, but found llvm-gcc or clang instead, though that problem is coming up less frequently. I don't use many exotic extensions so YMMV.