Fixes resolution of relative paths when running clang tools.

The chdir is not the perfect fix, as it is thread hostile. The
real fix will be to make -working-dir work correctly, which will
take time to implement. Before that, the tooling library cannot
be used concurrently.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156299 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed