I've placed a new GCC Frontend for PowerPC/MacOS X on the LLVM 1.5 Download page.
This frontend is identical to the previous one for 1.5, except that MacOS X header files that were fixed by the GCC build process are no longer included in the distribution. These header files should be fixed by running the fixheaders script included with the GCC Frontend.
If you have any problems using the new GCC frontend, please email the llvmdev list so that we can look into it.
-- John T.