Add the ability to display the default FIB number for a process to the
ps(1) utility, e.g. "ps -O fib".

bin/ps/keyword.c:
Add the "fib" keyword and default its column name to "FIB".

bin/ps/ps.1:
Add "fib" as a supported keyword.

sys/compat/freebsd32/freebsd32.h:
sys/kern/kern_proc.c:
sys/sys/user.h:
Add the default fib number for a process (p->p_fibnum)
to the user land accessible process data of struct kinfo_proc.

Submitted by: Oliver Fromme <olli@fromme.com>, gibbs