Odd checksum issue on MacOS

[Louis Guillaume <louis%zabrico.com@localhost>]

During a recent pkg_rolling-replace -vu, it failed while rebuilding 
devel/libcfg+ with a checksum error:

=> Applying pkgsrc patches for libcfg+-0.7.0
**************************************
Ignoring patch file 
/System/Volumes/Data/zabrico/pkgsrc/devel/libcfg+/patches/patch-ab: 
invalid checksum
**************************************
ERROR: Patching failed due to modified or broken patch file(s):
ERROR: 	/System/Volumes/Data/zabrico/pkgsrc/devel/libcfg+/patches/patch-ab
*** Error code 1

Stop.


However - this checksum error doesn't happen on NetBSD. I'm running 
MacOS "Monterey" (Darwin 21.6.0), Xcode 14.2, and using the 
pkgsrc-2022Q4 branch.

The MacOS system is using the same tree as the NetBSD one, over NFS 
(read only). I had set the "rebuild" flag to YES for all packages after 
upgrading the OS and Xcode.

In the meantime I've unset the "rebuild" flag for this package since the 
version is the same, so that everything else builds (hopefully).

It would be great if someone could duplicate the issue. But in any case 
- what would cause digest to get the wrong answer here?

--
Louis