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

lib/libstand/Makefile

@@ -135,24 +135,23 @@ SRCS+=	bzlib.c crctable.c decompress.c huffman.c randtable.c
 # decompression functionality from libz
 .PATH: ${.CURDIR}/../libz
 CFLAGS+=-DHAVE_MEMCPY -I${.CURDIR}/../libz
-SRCS+=	adler32.c crc32.c _infback.c _inffast.c _inflate.c \
-	_inftrees.c _zutil.c _zutil.h
-
-# aargh
-.for file in zutil.h
-CLEANFILES+=	_${file} _${file}.orig
-
-_${file}: ${file} ${file}.diff
-	patch -s -b .orig -o ${.TARGET} < ${.ALLSRC:M*.diff} ${.ALLSRC:M*.[ch]}
-.endfor
+SRCS+=	adler32.c crc32.c libstand_zutil.h
 
 .for file in infback.c inffast.c inflate.c inftrees.c zutil.c
+SRCS+=	_${file}
 CLEANFILES+=	_${file}
 
 _${file}: ${file}
-	sed "s|zutil\.h|_zutil.h|" ${.ALLSRC} > ${.TARGET}
+	sed "s|zutil\.h|libstand_zutil.h|" ${.ALLSRC} > ${.TARGET}
 .endfor
 
+# depend on stand.h being able to be included multiple times
+libstand_zutil.h: ${.CURDIR}/../libz/zutil.h
+	sed -e 's|<stddef.h>|"stand.h"|' \
+	    -e 's|<string.h>|"stand.h"|' \
+	    -e 's|<stdlib.h>|"stand.h"|' \
+	    ${.ALLSRC} > ${.TARGET}
+
 # io routines
 SRCS+=	closeall.c dev.c ioctl.c nullfs.c stat.c \
 	fstat.c close.c lseek.c open.c read.c write.c readdir.c

lib/libstand/stand.h

@@ -62,6 +62,9 @@
  *	@(#)stand.h	8.1 (Berkeley) 6/11/93
  */
 
+#ifndef	STAND_H
+#define	STAND_H
+
 #include <sys/types.h>
 #include <sys/cdefs.h>
 #include <sys/stat.h>
@@ -408,3 +411,5 @@ void Free(void *, const char *, int);
 #define free(x)		Free(x, NULL, 0)
 #define realloc(x, y)	Realloc(x, y, NULL, 0)
 #endif
+
+#endif	/* STAND_H */

lib/libstand/zutil.h.diff

@@ -1,15 +0,0 @@
-$FreeBSD$
---- zutil.h	Fri Jun 28 23:58:21 2002
-+++ zutil.h	Fri Jun 28 23:56:24 2002
-@@ -15,11 +15,7 @@
- 
- #include "zlib.h"
- 
--#ifdef STDC
--#  include <stddef.h>
--#  include <string.h>
--#  include <stdlib.h>
--#endif
-+#include "stand.h"
- #ifdef NO_ERRNO_H
-     extern int errno;