This allows llvm-rc to parse user-defined resources (ref:
msdn.microsoft.com/en-us/library/windows/desktop/aa381054.aspx).
These statements either import files, or put the specified raw data in
the resulting resource file.
Thanks to Nico Weber for his original work in this area.
Differential Revision: https://reviews.llvm.org/D37033
llvm-svn: 314478