currently _exit.2 has:
STANDARDS top
_exit()
POSIX.1-2008.
_Exit()
C11, POSIX.1-2008.
HISTORY top
POSIX.1-2001, SVr4, 4.3BSD.
_Exit() was introduced by C99.
the C99 for _Exit() is correct (so the C11 is wrong), and _exit() was
in POSIX before 2008:
https://pubs.opengroup.org/onlinepubs/7908799/xsh/_exit.html --- but
then maybe i misunderstand the difference between STANDARDS and
HISTORY because i don't really see why both exist here. is STANDARDS
meant to be the _current_ standards? (in which case it's still wrong,
and should be C23?)
