Move OpenBSD diff(1) into minix/usr.bin

Editor's note: NetBSD uses GNU diff.

Change-Id: I15d4441c73e0c626d0e5fda8c8683d131fbcbc38

minix/commands/Makefile

@@ -7,7 +7,7 @@ SUBDIR=	add_route arp at backup btrace \
 	ci cleantmp co \
 	compress crc cron crontab \
 	decomp16 DESCRIBE devmand devsize dhcpd \
-	dhrystone diff diskctl \
+	dhrystone diskctl \
 	eject fbdctl \
 	fix format fsck.mfs \
 	gcov-pull host \

minix/usr.bin/Makefile

@@ -4,6 +4,7 @@
 SUBDIR+=	eepromread
 .endif # ${MACHINE_ARCH} == "earm"
 
+SUBDIR+=	diff
 SUBDIR+=	grep
 SUBDIR+=	mined
 SUBDIR+=	ministat

minix/usr.bin/diff/diffdir.c

@@ -176,7 +176,11 @@ getdiffdirentries(int fd, char *buf, int nbytes)
 	if(!(read_de = malloc(readlen)))
 		errx(1, "getdiffdirentries: can't malloc");
 
+#ifndef __minix
 	dentsbytes_actual = getdents(fd, (struct dirent *) read_de, readlen);
+#else /* __minix */
+	dentsbytes_actual = getdents(fd, read_de, readlen);
+#endif /* __minix */
 
 	if(dentsbytes_actual <= 0)
 		return dentsbytes_actual;