in order to facilitate uniform diagnostic message format between clang and llvm,
clang driver now passes the following options: -fdiagnostics-format, -fshow-column, -fms-compatibility-version to cc1as.
this fix consists of two parts, first one for llvm and the second part for clang.
this code review takes care of clang part, llvm part is here: https://reviews.llvm.org/D42677