devel/patch: update GNU patch to the latest version 2.8
- GC previous Debian patches, backport new upstream fixes: add missing filename quoting, enable merge, skip read-only check when output file specified, reject empty filenames
- On i386, apply the same fix as Debian for Hurd/i386
- The port now seemingly builds fine with BSD make(1)
- Install some standard documentation files
PR: 285796