Remove -ftraditional option, which gcc doesn't actually support. Make

using -traditional and -traditional-cpp with clang an error because 
it's unsupported in clang and causes a significant change in the 
semantics of the language.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75690 91177308-0d34-0410-b5e6-96231b3b80d8