Backports for GHC 9.2
Fix two Darwin binary distribution issues noticed in testing the last attempt at a release candidate:
- !6385 (closed) for #20253 (closed)
- !6384 (closed) for #20254 (closed)
- Split of
Adjustor.cfrom !6155 (closed) to move Libffi checks to configure time - !5523 (closed), fixing #19683 (closed)
- !5944 (merged), fixing the OpenBSD build