I just tried to apply your patch psql-setfileref-initial.patch (using git apply) to the newest revision of postgres at the time (da6c4f6ca88) and it failed to patch startup.c. Thinking that the patch was for some previous revision, I then checked out d062245b5, which was from 2016-08-31, and tried applying the patch from there. I had the same problem:
$ git apply psql-setfileref-initial.patch error: patch failed: src/bin/psql/startup.c:106 error: src/bin/psql/startup.c: patch does not apply
However, when I applied the changes to startup.c manually and removed them from the patch, the rest of the patch applied without a problem. I don't know if I may have done something wrong in trying to apply the patch, but you may want to double check if you need to regenerate your patch from the latest revision so it will apply smoothly for reviewers.
Thank you for info. I'll do it immediately.
Regards
Pavel
In the meantime, I haven't had a chance to try out the fileref feature yet but I'll give it a go when I get a chance!