Saves us from doing a malloc/free call for every item on the list. ok op@

suggested by millert ok thomas_adam

Same problem as fixed in 90de04bc7f1b85b9c491bcd124f6178fad005de1. ok stsp

Found by our cherrypick regression tests.

Annoying bug which we inherited from OpenRCS which inherited it from OpenBSD's diff3 program. ok tracey millert

This has been shown to prevent mis-merges in some cases. It's probably not a final solution. We should look at what Git's "recursive merge" is doing and implement something similar. Keep using Myers during update/unstage. The advantage of Myers is that it produces smaller conflict chunks, and there are no known cases of mis-merges which affect update/unstage.

problem found by jrick ok millert

Myers diff tends to divide files into smaller diff chunks, while Patience diff attemps to maximize the size of diff chunks. Smaller diffs chunks generally result in a more managable presentation of merge conflicts.

ok millert, naddy

This new diff implementation was started by Neels Hofmeyr during the u2k20 hackathon and now replaces diffreg.c code lifted from the OpenBSD base system. The integration of this code into Got was done by me. Got now uses the patience diff algorithm by default. The diff.git repository will remain the primary repository for the diff code, which already compiles and runs on other operating systems such as Linux. Any fixes and improvements for files inherited from the diff.git repository should be written against that repository and synced to got.git afterwards.

We are not sure whether a gotweb package can own /var/www/tmp on OpenBSD. Moving gotweb's tmp dir to /var/www/got/tmp sidesteps that issue.