llvm-dwp: Handle dwo files produced by GCC

To start with, handle DW_FORM_string names. Follow up commit will handle
the interesting quirk with type units I was originally aiming for here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265452 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed