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

[ro at gcc dot gnu.org]

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

--- Comment #4 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 33916
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33916&action=edit
proposed patch