Re-apply TestHelp.py fix



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@185570 91177308-0d34-0410-b5e6-96231b3b80d8
Add missing -std=c99 flag to appease GCC 4.6
- this issue was detected on recent GCC buildbot runs



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@185571 91177308-0d34-0410-b5e6-96231b3b80d8