[Bug libstdc++/65928] std::find_if compilation errors

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65928

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
It's unspecified whether any of your headers includes <locale>, and in our
implementation <string> includes it.