Make compiler-rt/trunk/lib/asan compileable with Visual Studio 2008 on Windows.

Patch by Timur Iskhodzhanov (timurrrr@google.com)

To test:
$ cl /c *.c*
in the asan directory.

The code fails to link if you omit the "/c" part but that's one of the
next steps,
as well as a few TODO's I've put into the Windows-specific code.

llvm-svn: 149130