Provide basic support for dynamically loadable coff objects. Only handles a subset of x64 currently. Patch by Andy Ayers! Differential Revision: http://reviews.llvm.org/D7793 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231574 91177308-0d34-0410-b5e6-96231b3b80d8