Address some of the concerns by Chandler.

* s/AddDirectoryList/addDirectoryList/
* Move the call to ::getenv into the function.
* FileCheck-ize the testcase.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152583 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed