[Bug libstdc++/93469] memory header fails to compile with _XOPEN_SOURCE macro defined and -std=c++2a option specified

[vital.had at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93469

--- Comment #12 from Sergey Fedorov <vital.had at gmail dot com> ---
(In reply to Jonathan Wakely from comment #10)

The same error happens even without the macro in question being passed, at
least explicitly. Getting it with gcc 14.2.0 and ICU 76.1 (on x86_64, but not
on powerpc).