Upgrade the "excess elements in array initializer" warning to an error, since both C99 and C++ consider it an error. For reference, GCC makes this a warning while G++ makes it an error. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63435 91177308-0d34-0410-b5e6-96231b3b80d8