C11 allows typedefs to be redefined. Implement this in C11 mode, and
downgrade the default-error warning to an ExtWarn in
C90/99. <rdar://problem/10668057>


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147925 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed