currently we require GNU patch, version at least 2.7 (from 2009).
In particular, BSD patch does not know about --no-backup-if-mismatch, something that Sage used. An equivalent, and known to BSD patch as well as GNU patch, option is --posix.

So we could use --posix and change spkg-configure to accept BSD patch too.
I am not sure what's needed to be checked, besides that --posix is accepted. Something to learn from https://savannah.gnu.org/forum/forum.php?forum_id=7361 ?

Depends on #30668

CC: @thierry-FreeBSD @orlitzky

Component: build: configure

Author: Dima Pasechnik

Branch/Commit: u/dimpase/config/acceptposixpatch @ e0fcafc

Issue created by migration from https://trac.sagemath.org/ticket/30481