JITer (short path is added for darwin). This is needed to properly JIT llvm-gcc-4.2-built
binaries, since cxa_atexit is enabled by default on much more targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40600 91177308-0d34-0410-b5e6-96231b3b80d8