Bugfix for making the DWARF debug strings and labels to code emitted as secrel32 instead of long opcodes (only for coff). This makes them debuggable with GDB (with fix for 64bits msvc)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187656 91177308-0d34-0410-b5e6-96231b3b80d8