Since CMake is written in C++98 any clang-format configuration must
set `Standard` to `Cpp03` so that `A<A<int> >` is not rewritten as
`A<A<int>>`. However, this will cause `U"foo"` to be rewritten as
`U "foo"`. Add markup to turn clang-format off in the one place
that the latter case occurs so that we do not need a separate
`.clang-format` config file for it.
Inspired-by: Daniel Pfeifer <daniel@pfeifer-mail.de>
Brad King
Stephen Kelly