This is in net/nmap now.

net/ndiff/Makefile

@@ -1,22 +0,0 @@
-#   $OpenBSD: Makefile,v 1.8 2007/09/15 22:36:55 merdely Exp $
-
-COMMENT=	compare two nmap scans and outputs the differences
-
-DISTNAME=	NDiff-0.04
-PKGNAME=	${DISTNAME:L}p1
-CATEGORIES=	net perl5
-
-MASTER_SITES=	${MASTER_SITE_PACKETSTORM:=UNIX/nmap/}
-
-MAINTAINER=	Brian Caswell <bmc@openbsd.org>
-
-PERMIT_PACKAGE_CDROM=	Yes
-PERMIT_PACKAGE_FTP=	Yes
-PERMIT_DISTFILES_CDROM=	Yes
-PERMIT_DISTFILES_FTP=	Yes
-
-RUN_DEPENDS=	:nmap-*:net/nmap
-
-CONFIGURE_STYLE= perl
-
-.include <bsd.port.mk>

net/ndiff/distinfo

@@ -1,5 +0,0 @@
-MD5 (NDiff-0.04.tar.gz) = djLFGldb1et63GvyWPS37Q==
-RMD160 (NDiff-0.04.tar.gz) = oukbJL0mp7AC68lwScgilTk50NI=
-SHA1 (NDiff-0.04.tar.gz) = KM91X+jgZG91g7JHOJQKN9dCN44=
-SHA256 (NDiff-0.04.tar.gz) = 93nw3FtexyBJFQlrmGOxt8XH+geBgcFdvOtK+w/Qyv8=
-SIZE (NDiff-0.04.tar.gz) = 41176

net/ndiff/pkg/DESCR

@@ -1,5 +0,0 @@
-ndiff compares two nmap scans and outputs the differences.  It
-allows monitoring of your network(s) for interesting changes in
-port states and visible hosts.  Viewing results in this manner
-eliminates the need to sift through voluminous raw scan output
-in search of the few noteworthy differences.

net/ndiff/pkg/PLIST

@@ -1,20 +0,0 @@
-@comment $OpenBSD: PLIST,v 1.4 2005/09/05 13:12:47 espie Exp $
-bin/ndiff
-bin/ndiff2html
-bin/ngen
-bin/nrun
-${P5SITE}/PortScan/
-${P5SITE}/PortScan/DataStore.pm
-${P5SITE}/PortScan/NmapFile.pm
-${P5SITE}/PortScan/PortSpec.pm
-${P5SITE}/PortScan/ScanComparison.pm
-${P5SITE}/PortScan/ScanContext.pm
-${P5SITE}/PortScan/ScanSet.pm
-${P5SITE}/PortScan/ScannedHost.pm
-${P5SITE}/PortScan/SetOps.pm
-${P5SITE}/PortScan/ndiff.conf.sample
-@man man/man1/ndiff.1
-@man man/man1/ndiff2html.1
-@man man/man1/ngen.1
-@man man/man1/nrun.1
-@man man/man3p/NDiff_Quickstart.3