Add warning flag -Winvalid-pp-token for preprocessing-tokens which have
undefined behaviour, and move the diagnostic for '' from an Error into
an ExtWarn in this group. This is important for some users of the preprocessor,
and is necessary for gcc compatibility.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159335 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed