Driver: ArgList::getLastArg was in fact returning the first matching arg.
 - <rdar://problem/6715818> clang doesn't honor gcc semantic that last
    -O optimization option wins.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67628 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed