Add support for an additional mach message trap endpoint when available.
<rdar://problem/84827214>
Created attachment 443558 [details] Patch
Created attachment 443570 [details] Patch
Created attachment 443590 [details] Patch
Comment on attachment 443590 [details] Patch R=me.
Committed r285433 (243989@main): <https://commits.webkit.org/243989@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 443590 [details].