xcode build issue

I was wondering is anybody has seen this build issue with xcode 6.1 and the latest LLVM trunk:

I get build errors about the file llvm/llvmtrunk/llvm/projects/compiler-rt/lib/builtins/x86_64/floatundidf.S. The build errors appear to indicate that it's being treated as a C file, not an assembly file. Even weirder, the .o file for it is there... It's like somehow there is a leftover file that is being interpreted as a C file after a successful build...