Replace trivial use of external rc.exe by writing our own .res file.

This patch removes the dependency on the external rc.exe tool by writing
a simple .res file using our own library. In this patch I also added an
explicit definition for the .res file magic.  Furthermore, I added a
unittest for embeded manifests and fixed a bug exposed by the test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306311 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed