[Bug libgomp/82428] Builtins for openacc gang/worker/vector id/size

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82428

--- Comment #6 from Tom de Vries <vries at gcc dot gnu.org> ---
Approved for stage1 here:
https://gcc.gnu.org/ml/gcc-patches/2018-01/msg01576.html

Version to commit: https://gcc.gnu.org/ml/gcc-patches/2018-01/msg01630.html