[Bug libobjc/63765] [5.0 Regression] libobjc testsuite failures on AIX caused by setting _XOPEN_SOURCE

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63765

--- Comment #5 from David Edelsohn <dje at gcc dot gnu.org> ---
If _XOPEN_SOURCE is removed from thr.c completely, the testsuite results revert
to 1 failure.