[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 #1 from Tom de Vries <vries at gcc dot gnu.org> ---
Created attachment 42991
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42991&action=edit
Tentative patch, tested on host