We still use the -traditional-cpp to disable Apple's
custom precompiler. -traditional-cpp is deprecated for
this purpose because it will break once the Developer
Tools are updated to GCC 3. The -no-cpp-precomp flag
has the same effect and will continue to work in the
future. The attached patch fixes this. The patch was
taken against HEAD as of September 25 and must be
applied to xc/config/cf/darwin.cf.