Temporary readd GNU diff

etcupdate requires --change-group-format it is not easy to implement
in bsd diff so for now readd GNU diff

Makefile.inc1

@@ -1936,7 +1936,7 @@ native-xtools: .PHONY
     ${_clang} \
     sbin/md5 \
     sbin/sysctl \
-    usr.bin/diff \
+    gnu/usr.bin/diff \
     usr.bin/awk \
     usr.bin/basename \
     usr.bin/bmake \

ObsoleteFiles.inc

@@ -49,8 +49,6 @@ OLD_FILES+=sbin/ipftest
 OLD_FILES+=sbin/ipresend
 # 20170311: Remove WITHOUT_MANDOCDB option
 OLD_FILES+=usr/share/man/man1/makewhatis.1.gz
-# 20170311: remove GNU diff
-OLD_FILES+=usr/share/man/man7/diff.7.gz
 # 20170308: rename some tests
 OLD_FILES+=usr/tests/bin/pwait/pwait
 OLD_FILES+=usr/tests/usr.bin/timeout/timeout

UPDATING

@@ -69,11 +69,6 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 12.x IS SLOW:
 	removed as the userland we provide cannot use them. The KMS version
 	(sys/dev/drm2) support the same hardware.
 
-20170311:
-	GNU diff has been replaced by a BSD licensed diff. Some features of GNU
-	diff has not been implemented, if those are needed a newer version of
-	GNU diff is available via the diffutils package under the gdiff name.
-
 20170302:
 	Clang, llvm, lldb, compiler-rt and libc++ have been upgraded to 4.0.0.
 	Please see the 20141231 entry below for information about prerequisites

gnu/usr.bin/Makefile

@@ -17,7 +17,7 @@ SUBDIR_DEPEND_gdb=	binutils
 .endif
 
 SUBDIR.${MK_GCC}+=	cc
-SUBDIR.${MK_GNU_DIFF}+=	diff3
+SUBDIR.${MK_GNU_DIFF}+=	diff diff3
 SUBDIR.${MK_GNU_GREP}+=	grep
 SUBDIR.${MK_GPL_DTC}+=	dtc
 SUBDIR.${MK_TESTS}+=	tests

gnu/usr.bin/diff/Makefile

@@ -0,0 +1,36 @@
+# $FreeBSD$
+
+.include <src.opts.mk>
+
+DIFFSRC=${.CURDIR}/../../../contrib/diff/src
+.PATH: ${DIFFSRC} \
+       ${.CURDIR}/../../../contrib/diff/lib \
+       ${.CURDIR}/../../../contrib/diff/man \
+       ${.CURDIR}/../../../contrib/diff/doc
+
+PROG=	diff
+SRCS=   analyze.c context.c diff.c dir.c ed.c ifdef.c io.c \
+	normal.c side.c util.c \
+	xmalloc.c strtoumax.c cmpbuf.c exitfail.c error.c quotesys.c \
+	strftime.c c-stack.c basename.c exclude.c hard-locale.c \
+	file-type.c posixver.c prepargs.c version-etc.c
+
+# Important for ctype macros!
+CFLAGS+=-funsigned-char
+
+CFLAGS+=-DHAVE_CONFIG_H
+CFLAGS+=-DPR_PROGRAM=\"/usr/bin/pr\"
+CFLAGS+=-I${.CURDIR}/../../../contrib/diff
+CFLAGS+=-I${.CURDIR}/../../../contrib/diff/src
+CFLAGS+=-I${.CURDIR}/../../../contrib/diff/lib
+CFLAGS+=-I${DESTDIR}/usr/include/gnu
+
+MAN=	diff.1 diff.7
+
+LIBADD+=	gnuregex
+
+.if ${MK_TESTS} != "no"
+SUBDIR+=	tests
+.endif
+
+.include <bsd.prog.mk>

gnu/usr.bin/diff/Makefile.depend

@@ -0,0 +1,19 @@
+# $FreeBSD$
+# Autogenerated - do NOT edit!
+
+DIRDEPS = \
+	gnu/lib/csu \
+	gnu/lib/libgcc \
+	gnu/lib/libregex \
+	include \
+	include/xlocale \
+	lib/${CSU_DIR} \
+	lib/libc \
+	lib/libcompiler_rt \
+
+
+.include <dirdeps.mk>
+
+.if ${DEP_RELDIR} == ${_DEP_RELDIR}
+# local dependencies - needed for -jN in clean tree
+.endif

gnu/usr.bin/diff/tests/Makefile

@@ -0,0 +1,15 @@
+# $FreeBSD$
+
+PACKAGE=	tests
+
+TESTSRC=	${SRCTOP}/contrib/netbsd-tests/usr.bin/diff
+
+NETBSD_ATF_TESTS_SH=	diff_test
+ATF_TESTS_SH_SED_diff_test=	-e 's/t_diff/`basename $$0`/g'
+
+${PACKAGE}FILES+=	d_mallocv1.in
+${PACKAGE}FILES+=	d_mallocv2.in
+
+.include <netbsd-tests.test.mk>
+
+.include <bsd.test.mk>

gnu/usr.bin/diff/tests/Makefile.depend

@@ -0,0 +1,11 @@
+# $FreeBSD$
+# Autogenerated - do NOT edit!
+
+DIRDEPS = \
+
+
+.include <dirdeps.mk>
+
+.if ${DEP_RELDIR} == ${_DEP_RELDIR}
+# local dependencies - needed for -jN in clean tree
+.endif

usr.bin/Makefile

@@ -34,7 +34,6 @@ SUBDIR=	alias \
 	csplit \
 	ctlstat \
 	cut \
-	diff \
 	dirname \
 	du \
 	elf2aout \