[Bug testsuite/81690] libgomp.c/{target-32,thread-limit-2}.c fail for nvptx: missing usleep

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81690

--- Comment #7 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to Tobias Burnus from comment #6)
> for a busy-wait implementation, which was supposed get rewritten (see next
> message in thread) "using declare variant".
The missing bit referenced there is:
 https://gcc.gnu.org/ml/gcc-patches/2019-11/msg01493.html