Don't use a patch w/in /usr/src. Programmatically change files when needed.

usr.bin/bzip2/doc/Makefile

@@ -6,9 +6,9 @@ INFO=	bzip2
 INFOSECTION=	"Programming & development tools."
 MAKEINFOFLAGS=	--no-validate
 
-CLEANFILES+=	bzip2.texi bzip2.texi.orig
+CLEANFILES+=	bzip2.texi
 
-bzip2.texi:	manual.texi manual.texi.diff
-	patch -s -b .orig -o ${.TARGET} < ${.ALLSRC:M*.diff} ${.ALLSRC:M*.texi}
+bzip2.texi:	manual.texi
+	grep -v '^@bf{' ${.ALLSRC} > ${.TARGET}
 
 .include <bsd.info.mk>

usr.bin/bzip2/doc/manual.texi.diff

@@ -1,22 +0,0 @@
-$FreeBSD$
-
---- manual.texi	2002/02/01 16:00:45	1.1
-+++ manual.texi	2002/02/01 16:01:11
-@@ -46,8 +46,6 @@
- find it identical to that contained in the file LICENSE in the 
- source distribution.
- 
--@bf{------------------ START OF THE LICENSE ------------------}
--
- This program, @code{bzip2}, 
- and associated library @code{libbzip2}, are
- Copyright (C) 1996-2002 Julian R Seward.  All rights reserved.
-@@ -89,8 +87,6 @@
- @code{jseward@@acm.org}
- 
- @code{bzip2}/@code{libbzip2} version 1.0.2 of 30 December 2001.
--
--@bf{------------------ END OF THE LICENSE ------------------}
- 
- Web sites:
-