Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

2 long double constants were missing L suffixes. This helped break tanl()
on !(amd64 || i386). It gave slightly worse than double precision in some
cases. tanl() now passes tests of 2^24 values on ia64.

Fix a typo which broke k_tanl.c on !(amd64 || i386).

Add kernel functions for 80-bit long doubles. Many thanks to Steve and
Bruce for putting lots of effort into these; getting them right isn't
easy, and they went through many iterations.

Submitted by: Steve Kargl <sgk@apl.washington.edu> with revisions from bde