Import mdocml-1.12.2
idr: Protect data structures with a lwkt_token

Using spinlocks is not a good idea when you have to allocate memory
idr: Grow descriptor table as needed in idr_get_new_above()
Merge branch 'vendor/MDOCML'

Conflicts:
	contrib/mdocml/mandoc.3
	contrib/mdocml/mdoc_macro.c
mdocml: refresh config.h and README.DRAGONFLY
mdocml: teach libmandoc(3) about ``libmandoc''
man: fix literal file suffix parsing regression

Some man pages have dots in their names, apparently.  Fixes
the following invoke:

    # man ./man.conf.5

This, however, doesn't fix parsing of e.g. "./man..conf.4.5".
Instead the suffix list should be searched for a real match
while also preserving their matching order.  In the meantime,
please don't do this (ever).

Noticed-by: Thomas Klausner via NetBSD
idr: idr_pre_get() takes two arguments

Don't diverge from the well-known Linux API