Allows 'got commit' to use a ".diff" suffix for temporary diff files. ok op@

This behaviour is already documented in got-worktree(5) but wasn't actually implemented. ok stsp@

ok op@

Reported by stsp on IRC: got patch failed to set the x-bit for a new file despite got diff recording mode 755. Parse got and git diffs for this data and set file modes accordingly. Tweaked with hint from op. ok stsp@

suggested by stsp@; no functional change.

it's useful for e.g. to apply old patches that weren't generated by `got diff' or git-diff(1) and so lacks the metadata needed for the 3-way merge. manpage improvements from and ok stsp@

Current code is overly complex; it looks if the diff *might* use diff3 merge to postpone reverse_patch until we know for sure. Instead, just reverse_patch in apply_patch once we know if merge *is* used or not.

`got patch -R' fails spectacularly when applied on a diff that contains the info of the original blob for the diff3 merge machinery since it tries to apply the reverse of the patch to the old blob. change it to run the patch (_not_ reversed) on the old blob and then swap the arguments to got_diff3_merge which gives us the correct reverse merge of the diff. while here add a test case too. reported by naddy, discussed with and ok stsp@

ok stsp@

Reminded by naddy and stsp; it was missing a cast to unsigned char to prevent issues on archs with signed chars and was too broad anyway. While here, drop an extra check immediately after. ok stsp@

This makes 'got patch' try to ignore whitespaces when trying to match a hunk. Discused with and ok stsp@

This fixes a regression introduced with the diff3 merge: files merged this way have their permissions resetted after patch. The issue is due the fact that patch_file looks at a temporary files and not at the original "old file". Reported by and ok stsp@

Make the choice of diff algorithm configurable by diff API users. The got and gotweb programs keep using Patience diffs which are prettier than Myers. But tog should be as fast as possible since it is being used interactively. If performance of Patience diff gets improved later we can consider switching tog back over to it. ok tracey jamsek

tweak and ok stsp@

ok stsp@

Suggested by stsp@. This makes possible to tell if 'got patch' used a merge-base from the repository for the 3-way merge or did a simple search/replace operation. While here update the tests to look for the 'G' status and the manpage, which was also missing the documentation for the 'C' status in got patch. ok stsp@

since diffs are often enclosed in other formats (e.g. emails) we might parse something and think it's a blob id when it's not. This should already happens, but apply_patch is looking for the wrong error due to a leftover from previous attempts. Reported by stsp@ while here tweak the test_patch_merge_unknown_blob to also try with a dummy commit id, as now got-read-patch requires it in order to consider a blob id. ok stsp@

suggested by and ok stsp@

Parse the "blob -" metadata in diffs produced by 'got diff' and use the original file for patching. Then, use the diff3 with the current version of the file to merge the differences. This solves many failures automagically or at least turns them into a conflict. ok/improvements stsp@

future work with diff3 merge will need the fully patched file even in the nop mode ok stsp@

ok stsp@