Following changes are done.
Add missing headers.
Replace _snprintf with snprintf. It is already changed to _snprintf for MSVC.
Add a file in the build for autoconf.
Call DynamicLoaderWindows::Terminate and DynamicLoaderWindows::Initialize only for MSVC build.
Reviewed in http://reviews.llvm.org/D7536.
llvm-svn: 228822