[PATCH] [PECOFF] Support linking against DLL.

[Rui Ueyama]

  Looks like we can use yaml2obj for simple binaries, with a fix for a bug that yaml2obj cannot handle symbol name starting with "@".

  Is there any way to create an archive file using yaml2obj? I think I can create an archive file with yaml2obj and llvm-ar but it's a bit awkward.

http://llvm-reviews.chandlerc.com/D1096