Migrate machine and hostname identification from fishd.cpp to
env_universal_common.cpp, so that fish can use it
Beginning steps towards teaching the universal variable system to read
the fishd file directly, instead of fetching it through fishd
Implement atomic loading/saving of fishd file within fish, eventually
permitting removal of fishd. Universal variables test passes, others
fail.
Correctly invoke callbacks with fishd-less universal variables. All
tests now pass.
Merge branch 'master' into death_of_fishd
Include a header to permit building on Linux
Enhance file_id_t to have richer information, to guard against inode
recycling on Linux filesystems
Include a missing header for uint64_t
Move universal variable callbacks out from under the lock, to avoid a
possible deadlock on reentrancy
Implement shared memory strategy for universal variable notifications
Implement universal variable deletion. Adopt shared memory uvar notification.
Implement deletion of universal variables. Add tests for them.
Merge remote-tracking branch 'origin/death_of_fishd' into death_of_fishd
Implement notifyd-based notification strategy for universal variables
(OS X specific)
Early implementation of inotify-based universal variable notifier for
Linux
Merge branch 'master' into death_of_fishd

Conflicts:
	configure.ac
Re-establish inotify watch when file is deleted
Merge branch 'death_of_fishd' of https://github.com/fish-shell/fish-shell into death_of_fishd
Make inotify-based universal variable notifier tests pass
Initial work on strategy_named_pipe universal notifier.