Debian is working towards reproducible biuld (https://wiki.debian.org/ReproducibleBuilds)
Currently check is not reproudicble, as for example it embeds timestamps in the documentation. The timestamps are in the patches for the examples.
The patch removes those timetamps.
The patch is also here: http://anonscm.debian.org/cgit/collab-maint/check.git/tree/debian/patches/05no-timestamp-in-check-info.patch
Thanks for considering!
Never considered that using diff would result in the build output not being reproducible. Interesting.
We'll accept the patch, though will modify it slightly so that if the filterdiff tool is not installed the example will still build. You can see the change here.
If you find anything else that is not reproduciable in Check's build output, let us know.