[Bug c++/69683] multiline raw string R"()" for C++11 warning in false #ifdef when -std=c++98

[jcrada at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69683

--- Comment #2 from Juan Rada-Vilela <jcrada at gmail dot com> ---
Indeed, it is unfortunate, especially because I compile my software with
`-Werror`, so now I have to choose between ignoring warnings or using raw
strings. Is there anything I can do to avoid triggering a warning and yet use a
raw string?