I managed to get the llvm tool chain compiled on my windows machine
using mingw a couple of weeks ago.
Have you tried to build llvm-gcc by yourself?
$ llvm-gcc hello.c -o hello.exe
ld: crt2.o: No such file: No such file or directory
Normally crt*.o files are built during normal gcc build process
(llvm-gcc as well). However, mingw32 runtime has its own crt*.o files,
which are included with binary distribution of llvm-gcc4 (mingw32
ERROR: Program used external function '_alloca' which could not be resolved!
Right. _alloca is inside runtime code, not bytecode. lli was not touched
to get mingw32 compatibility. I'll take a look.