For -Wignored-qualifiers, don't warn on qualifiers which we acquire via a
typedef. Also don't warn on the _Atomic type specifier, just on the _Atomic
type qualifier.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178218 91177308-0d34-0410-b5e6-96231b3b80d8