Expose panicstr and system_inshutdown for zfs_vfs_sync
Implement VN_RELE_ASYNC using threads. Only used in 2 places.
Silence missing API calls now handled by zed.
Info.plist cleanup
Move OSBundleAllowUserLoad to end of plist
rsync -a equals -rlptgoD so -r is redundant
name cache update is not quite right
WIP: Allocator overhead reduction. Use of built in SPL infrastructure
     such as lists, rather than bespoke. Merge down to a single compilation
     unit.