things in crypt.3, and create MLINKS

- new entries, taken from arla source tree
- a few comments about cache sizes by me
Unfortunately, the default cache size must be very small (20M),
because the CD currently recommends a /var partition of 25M.

ok tdeval@

for ENAMETOOLONG, though since we use strlcpy() and strlcat() this
is not a big deal.  Problem found by vincent@

ok deraadt@

solves PR3376 by matthew.gream@pobox.com, fix slightly different
ok mcbride@ deraadt@

ok millert@

APIWARN; disabled by default.  In use by many developers for quite some time,
now they have a common knob to enable/disable this

millert ok

- extend_pgdir and malloc_make_chunks return int, not void*
ok tedu@

ok tedu@

ok tdeval@ henning@ millert@

checking for non-zero since an empty field is equivalent to 0.
Problem noted by Graeme Lee.

umask detection.

henning@ OK

reference it rather than /etc/netstart
ok henning@ millert@

millert@ ok

ok hin@ deraadt@ pb@

You must have an up-to-date gcc for this!
deraadt@ ok

ok millert@

ok deraadt@, millert@, jmc@, suggested by espie@