PR13529: Don't crash if the driver sees an unused input file when running as

For now, the test uses "REQUIRES: shell" to determine if the host system
supports "ln -s", which it uses to create a 'clang-cpp' symlink. This is a bit
hacky and should likely be directly supported by lit.cfg.

git-svn-id: 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed