strictier validation for data received from libexec helpers use correct error code and ok stsp@

drop unused variable

use strndup instead of malloc+memcpy Simplifies the reading of the author/committer string and makes also the code shorter. ok stsp@

don't check datalen when calling recv_imsg_error recv_imsg_error already checks the size of the message, and it does so more precisely than the removed code. ok stsp@

got patch: use ints for line offsets instead of longs ints have the advantage that their size is more likely to be the same across the various architecture supported by OpenBSD, thus introducing less possible differences. INT_MAX is still (at least) a few order of magnitudes higher than the patches we dealt with (even abnormal ones.) suggested by stsp@

actually guarding against negative line offsets previous commit looked at some pretty zeroes returned from calloc instead of the actual numbers received.

style; set datalen only once

got patch: guard against invalid (negative) line offsets under normal circumstances got-read-patch can't send negative line offsets; that's not an excuse not to guard the main process from those as well. This makes sure we bail out early instead of trying to apply the diff.

free patch on error

got patch: ensure new and old paths are NUL-terminated

fix error handling in find_pack_for_enumeration(); pointed out by op@

Bring back object enumeration inside got-read-pack as a fast path. The problem that was found in the earlier version has been fixed. ok op@

fix error case handling in print_commit_oneline(); pointed out by op@

remove outdated and overly-specific documentation of got log -s output ok op@

adjust expected test output after got log -s changes ok op@