# uname -a
FreeBSD testing.bullguard.com 6.2-BETA1 FreeBSD 6.2-BETA1 #0: Mon Sep 18 15:00:58 UTC 2006     root@meyers.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP  amd64


# pkg_info | grep -i autoconf
autoconf-2.13.000227_5 Automatically configure source code on many Un*x platforms 
autoconf-2.53_3     Automatically configure source code on many Un*x platforms 
autoconf-2.59_2     Automatically configure source code on many Un*x platforms 
gnu-autoconf-2.59   Automatically configure source code on many Un*x platforms 


[root@testing]:/usr/ports/lang/ruby18: # make install
<snip>
creating config.h
configure: creating ./config.status
config.status: creating Makefile
===>  Building for ruby-1.8.5,1
cd . && autoconf
autoconf: not found
*** Error code 127
</snip>