ADD STRTOD TO LIBC WHILE FIXING ATOF FP TRAP.

ADD STRTOD TO LIBC WHILE FIXING ATOF FP TRAP.

This version of atof checks for overflow conditions, rather
than simply causing a SIGFP.  It also takes advantage of the overlap
between atof() and strtod() functionality to finally implement the
long-missing strtod in libc (yay!).  Also adjusts awk's config.h to
live with this new fact.

[ Editor's note: ]

ALSO BE SURE TO READ THE TOP LEVEL README FILE FOR THE PATCH KIT.
There are important instructions on how to properly build things
after installing this patch.  If you do not do so, this patch will
not do anything for you.

AUTHOR:	Joerg Wunsch
386BSD-Patchkit: patch00089