The intention is to get a clean build of MRI 1.8.7 and 1.9.3.
MRI 1.8.7 doesn't play nicely with LLVM based GCC compilers. In Mountain Lion, the only way to get a non-LLVM gcc is to build one yourself. The command line tools package in Xcode 4.4 does not contain a non-llvm based GCC.
- Upgrade to Mountain Lion
- Remove all previous copies of Xcode