Firewalk Port Broken

[Phusion]

I'm running FreeBSD 5.2.1. I tried to install the firewalk port and
this is what I got. I got the dependencies of libdnet and libnet-devel
installed before trying firewalk.

%pwd
/usr/ports/security/firewalk
%sudo make
===>  Building for firewalk-5.0_1
Making all in src
cc -DHAVE_CONFIG_H -I. -I. -I../include   -I/usr/local/include  -O
-pipe -mcpu=pentiumpro -Wall -c init.c
init.c: In function `fw_init_net':
init.c:156: error: `BIOCIMMEDIATE' undeclared (first use in this function)
init.c:156: error: (Each undeclared identifier is reported only once
init.c:156: error: for each function it appears in.)
*** Error code 1

Stop in /usr/ports/security/firewalk/work/Firewalk/src.
*** Error code 1

Stop in /usr/ports/security/firewalk/work/Firewalk.
*** Error code 1

Stop in /usr/ports/security/firewalk.
%

I've already looked for answers, but no luck. I found that someone
else posted this same exact problem back in February or March of this
year to a FreeBSD mailing list, but no one responsed with how to fix
it. Also, I cvsuped the ports collection before doing this. Let me
know what you think the problem is. Thanks.

Phusion