llvm dev - Jul 2008 - [LLVMdev] Problem

Hi, I just downloaded the binaries for LLVM for mingw32 and I get this 
error:

C:\Downloads\llvm-gcc4.2-2.3-x86-mingw32\llvm-gcc4.2\bin>llvm-gcc a.c -o a
a.c:1: error: bad value (generic) for -mtune= switch

Any thoughts?
Thanks,
Willow