[PECOFF] Change the DLL entry symbol.
[PECOFF] Change the DLL entry symbol.

I'm not 100% sure but it looks like DLL entry symbol (DLL initializer function
name) should be _DllMainCRTStartup@12. The reason why I'm not very sure is
because I have no idea what "@12" suffix is, but without it the symbol won't
be resolved...

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@198072 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld