Why make llvm to be a dll?

Since DMD compiled binary is OMF, and I didn't try DMC to compile llvm on windows. 
To get llvm OMF binary seems a lot of tweaking of llvm building system. So dll 
came to my mind. Once dparser frontend part can be compiled by itself. The backend part
could take advantage of llvm-gcc compiling llvm (llvm backend code compiled to llvm 
byte code.) There, llvm-ld can link the backend byte code with the frontend part without
the DLL layer.



backend.exp is built from backend.def.
target.def is for further use(JIT and etc.)

buildbackenddll.bat illustrate a almost minimal compile command. 

pefixup.exe is borrowed from reactos. maybe it's not necessary.

Enjoy!