[Asterisk-bsd] /usr/local/include/zaptel.h:37:16: os.h: No such file or directory

[Graham S. Jarvis]

I have a problem with an asterisk-1.0.7 make on
FreeBSD xxxxxxxxxx 5.3-RELEASE FreeBSD 5.3-RELEASE #0: Fri Nov  5 04:19:18
UTC 2004     root at harlow.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386

The FreeBSD is a new install from the FreeBSD Mall 5.3 disc
I don't have more than DSL so I didn't want to update all the ports
collection, so I updated these

ports-base
ports-audio
ports-comms
ports-databases
ports-devel
ports-lang
ports-mail
ports-misc
ports-net
(did I forget anything?)

and I started the 'make install' from /usr/ports/net/asterisk

After going through all the dependencies I get

/usr/local/include/zaptel.h:37:16: os.h: No such file or directory

and make exits.

Any ideas?