Prevent an endless polling loop on Linux where POLLOUT and POLLHUP can both be reported via pollfd revents.

"thou shalt not include sys/cdefs.h because it is not standardized", and in this case is not really needed either.

We did consider making -d and -P options conflict but doing so would not be very helpful. Instead, document -d as a superset of -P. ok op, jamsek

If show_repo_age is set to off, got_get_repo_age() returns without setting the timestamp. got_get_repo_age() is also used by the branch listing to show how old they are however, and we end up rendering the stack garbage. Instead, respect `show_repo_age off' one layer above, and always return a timestamp in got_get_repo_age(). While here, initialize the timestamp to zero so it's set also in case of failures. Issue reported on IRC by xs, thanks!

When the current matched and selected entry is the last loaded commit, we keep looping the same code path because search_entry is always NULL. Before poking the log thread for more commits, set search_entry to the currently selected commit, which is where the search resumes. Patch by Mikhail

Plus multiple copypasta fixes where I was cmp(1)ing stdout instead of stderr! Fortunately, we were doing the right thing despite not checking it properly. The log -dPp test is from op@. ok + tweaks op@

Only collect changed paths once if both -d and -P are specified; we already checked for -d and -p. Reported by Lucas on IRC. Regress for this and the previous (got log -x keyword) commit still due. ok stsp@ and op@

Suggested by Lucas on IRC. ok stsp@ and op@

By incrementing the resize step from 64 to 256 deltifying takes less time on modestly sized files; the resize is still a small number instead of a fraction of the current table size (which would be more usual for a hash table) since this code is also used in gotd. ok stsp

it's a different way to spell the same number, but it's more evocative since the on-disk format is 32 bits wide. ok stsp

Use a local buffer instead of calling reallocarray() every 8 bytes; the speed up is measurable. The downside is that we're now limited to paths long at most PATH_MAX bytes, but since this is the fileindex it's not an issue in practice. ok jamsek stsp

This makes histedit folding work when a file is modified by commit A and then deleted in commit B, with A being folded into B. Problem reported by naddy@