Index: etc/mtree/BSD.tests.dist
===================================================================
--- etc/mtree/BSD.tests.dist
+++ etc/mtree/BSD.tests.dist
@@ -350,6 +350,10 @@
         ..
         libproc
         ..
+        libregex
+            data
+            ..
+        ..
         librt
         ..
         libsbuf
Index: lib/Makefile
===================================================================
--- lib/Makefile
+++ lib/Makefile
@@ -162,6 +162,7 @@
 .endif
 
 SUBDIR.${MK_EFI}+=	libefivar
+SUBDIR.${MK_LIBREGEX}+=	libregex
 SUBDIR.${MK_LIBTHR}+=	libthr
 SUBDIR.${MK_LLVM_LIBUNWIND}+=	libgcc_eh
 SUBDIR.${MK_LLVM_LIBUNWIND}+=	libgcc_s
Index: lib/libc/regex/Makefile.inc
===================================================================
--- lib/libc/regex/Makefile.inc
+++ lib/libc/regex/Makefile.inc
@@ -10,8 +10,11 @@
 
 SYM_MAPS+=${LIBC_SRCTOP}/regex/Symbol.map
 
+# manpages only included in libc version
+.if ${LIB} == "c"
 MAN+=	regex.3
 MAN+=	re_format.7
 
 MLINKS+=regex.3 regcomp.3 regex.3 regexec.3 regex.3 regerror.3
 MLINKS+=regexec.3 regfree.3
+.endif
Index: lib/libc/tests/regex/Makefile
===================================================================
--- lib/libc/tests/regex/Makefile
+++ lib/libc/tests/regex/Makefile
@@ -1,63 +1,7 @@
 # $FreeBSD$
 
-.include <bsd.own.mk>
-
 PACKAGE=	tests
 
-BINDIR=		${TESTSDIR}
-
-# SKIP_LEFTASSOC -> these testcases fail on FreeBSD.
-IMPLEMENTATION?=      -DREGEX_SPENCER -DSKIP_LEFTASSOC
-
-CFLAGS.h_regex+=-I${TESTSRC} -I${.CURDIR:H:H}/regex
-PROGS+=		h_regex
-SRCS.h_regex=	main.c split.c debug.c
-
-NETBSD_ATF_TESTS_SH=	regex_test
-
-${PACKAGE}FILES+=		README
-
-FILESGROUPS+=	${PACKAGE}DATA_FILES
-${PACKAGE}DATA_FILESPACKAGE=${PACKAGE}
-
-${PACKAGE}DATA_FILESDIR=	${TESTSDIR}/data
-${PACKAGE}DATA_FILES+=		data/anchor.in
-${PACKAGE}DATA_FILES+=		data/backref.in
-${PACKAGE}DATA_FILES+=		data/basic.in
-${PACKAGE}DATA_FILES+=		data/bracket.in
-${PACKAGE}DATA_FILES+=		data/c_comments.in
-${PACKAGE}DATA_FILES+=		data/complex.in
-${PACKAGE}DATA_FILES+=		data/error.in
-${PACKAGE}DATA_FILES+=		data/meta.in
-${PACKAGE}DATA_FILES+=		data/nospec.in
-${PACKAGE}DATA_FILES+=		data/paren.in
-${PACKAGE}DATA_FILES+=		data/regress.in
-${PACKAGE}DATA_FILES+=		data/repet_bounded.in
-${PACKAGE}DATA_FILES+=		data/repet_multi.in
-${PACKAGE}DATA_FILES+=		data/repet_ordinary.in
-${PACKAGE}DATA_FILES+=		data/startend.in
-${PACKAGE}DATA_FILES+=		data/subexp.in
-${PACKAGE}DATA_FILES+=		data/subtle.in
-${PACKAGE}DATA_FILES+=		data/word_bound.in
-${PACKAGE}DATA_FILES+=		data/zero.in
-#${PACKAGE}DATA_FILES+=		data/att/README
-${PACKAGE}DATA_FILES+=		data/att/basic.dat
-${PACKAGE}DATA_FILES+=		data/att/categorization.dat
-${PACKAGE}DATA_FILES+=		data/att/forcedassoc.dat
-${PACKAGE}DATA_FILES+=		data/att/leftassoc.dat
-${PACKAGE}DATA_FILES+=		data/att/nullsubexpr.dat
-${PACKAGE}DATA_FILES+=		data/att/repetition.dat
-${PACKAGE}DATA_FILES+=		data/att/rightassoc.dat
-
-NETBSD_ATF_TESTS_C=	exhaust_test
-NETBSD_ATF_TESTS_C+=	regex_att_test
-
-.for t in ${NETBSD_ATF_TESTS_C}
-CFLAGS.$t+=	-I${TESTSRC} ${IMPLEMENTATION}
-.endfor
-
-.include "../Makefile.netbsd-tests"
-
-LIBADD.regex_att_test+=	util
-
+.include "Makefile.inc"
+.include "${.CURDIR:H}/Makefile.netbsd-tests"
 .include <bsd.test.mk>
Index: lib/libc/tests/regex/Makefile.inc
===================================================================
--- lib/libc/tests/regex/Makefile.inc
+++ lib/libc/tests/regex/Makefile.inc
@@ -2,14 +2,12 @@
 
 .include <bsd.own.mk>
 
-PACKAGE=	tests
-
-BINDIR=		${TESTSDIR}
+BINDIR?=	${TESTSDIR}
 
 # SKIP_LEFTASSOC -> these testcases fail on FreeBSD.
 IMPLEMENTATION?=      -DREGEX_SPENCER -DSKIP_LEFTASSOC
 
-CFLAGS.h_regex+=-I${TESTSRC} -I${.CURDIR:H:H}/regex
+CFLAGS.h_regex+=-I${TESTSRC} -I${SRCTOP}/lib/libc/regex
 PROGS+=		h_regex
 SRCS.h_regex=	main.c split.c debug.c
 
@@ -56,8 +54,4 @@
 CFLAGS.$t+=	-I${TESTSRC} ${IMPLEMENTATION}
 .endfor
 
-.include "../Makefile.netbsd-tests"
-
 LIBADD.regex_att_test+=	util
-
-.include <bsd.test.mk>
Index: lib/libregex/Makefile
===================================================================
--- /dev/null
+++ lib/libregex/Makefile
@@ -0,0 +1,20 @@
+# $FreeBSD$
+
+.include <src.opts.mk>
+
+PACKAGE=lib${LIB}
+LIB=	regex
+SHLIB_MAJOR=	1
+SHLIB_MINOR=	0
+
+CFLAGS+=	-DLIBREGEX
+LIBC_SRCTOP=	${.CURDIR:H}/libc
+SYMBOL_MAPS=	${SYM_MAPS}
+
+.if ${MK_TESTS} != "no"
+SUBDIR+=	tests
+.endif
+
+.include "../Makefile.inc"
+.include "${LIBC_SRCTOP}/regex/Makefile.inc"
+.include <bsd.lib.mk>
Index: lib/libregex/tests/Makefile
===================================================================
--- /dev/null
+++ lib/libregex/tests/Makefile
@@ -0,0 +1,20 @@
+# $FreeBSD$
+
+PACKAGE=	tests
+TESTSRC=	${SRCTOP}/contrib/netbsd-tests/lib/libc/regex
+
+.PATH:		${SRCTOP}/tests
+
+.include "${SRCTOP}/lib/libc/tests/regex/Makefile.inc"
+
+ATF_TESTS_SH+=	libregex_test
+
+${PACKAGE}DATA_FILES+=	gnuext.in
+
+LIBADD.h_regex+=regex
+.for t in ${NETBSD_ATF_TESTS_C}
+LIBADD.$t+=	regex
+.endfor
+
+.include <netbsd-tests.test.mk>
+.include <bsd.test.mk>
Index: lib/libregex/tests/gnuext.in
===================================================================
--- /dev/null
+++ lib/libregex/tests/gnuext.in
@@ -0,0 +1,30 @@
+# BRE Quantifiers
+ab\?c	b	abc	abc
+ab\+c	b	abc	abc
+# BRE Branching
+abc\|de	b	abc	abc
+a\|b\|c	b	abc	a
+\(ab\|bc\)	b	abcd	ab
+# ERE Backrefs
+(ab)\1	-	ab
+(ab)\1	-	abab	abab
+\1(ab)	C	ESUBREG
+(a)(b)(c)(d)(e)(f)(g)(h)(i)\9	-	abcdefghii	abcdefghii
+# \w, \W, \s, \S (alnum, ^alnum, space, ^space)
+\w+	-	-%@a0X-	a0X
+\w\+	b	-%@a0X-	a0X
+\s+	-	aSNTb	SNT
+\s\+	b	aSNTb	SNT
+# Word boundaries (\b, \B, \<, \>, \`, \')
+# (is/not boundary, start/end word, start/end subject string)
+\babc\b	&	<abc>	abc
+\<abc\> &	<abc>	abc
+\Babc\B	&	abc
+\B[abc]\B	&	<abc>	b
+\B[abc]+	-	<abc>	bc
+\B[abc]\+	b	<abc>	bc
+\`abc\'	&	abc	abc
+\`.+\'	-	abNc	abNc
+\`.\+\'	b	abNc	abNc
+(\`a)	-	Na
+(a\')	-	aN
Index: lib/libregex/tests/libregex_test.sh
===================================================================
--- /dev/null
+++ lib/libregex/tests/libregex_test.sh
@@ -0,0 +1,55 @@
+#
+# Copyright (c) 2017 Kyle Evans <kevans@FreeBSD.org>
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+# $FreeBSD$
+
+check()
+{
+	local dataname="${1}"; shift
+
+	prog="$(atf_get_srcdir)/h_regex"
+	data="$(atf_get_srcdir)/data/${dataname}.in"
+
+	atf_check -x "${prog} <${data}"
+	atf_check -x "${prog} -el <${data}"
+	atf_check -x "${prog} -er <${data}"
+}
+
+create_tc()
+{
+	local name="${1}"; shift
+	local descr="${1}"; shift
+
+	atf_test_case "${name}"
+	eval "${name}_head() { atf_set 'descr' '${descr}'; }"
+	eval "${name}_body() { check '${name}'; }"
+
+	atf_add_test_case "${name}"
+}
+
+atf_init_test_cases()
+{
+	create_tc gnuext "Check GNU extension functionality"
+}
Index: share/mk/bsd.libnames.mk
===================================================================
--- share/mk/bsd.libnames.mk
+++ share/mk/bsd.libnames.mk
@@ -132,6 +132,7 @@
 LIBPTHREAD?=	${LIBDESTDIR}${LIBDIR_BASE}/libpthread.a
 LIBRADIUS?=	${LIBDESTDIR}${LIBDIR_BASE}/libradius.a
 LIBRDMACM?=	${LIBDESTDIR}${LIBDIR_BASE}/librdmacm.a
+LIBREGEX?=	${LIBDESTDIR}${LIBDIR_BASE}/libregex.a
 LIBROKEN?=	${LIBDESTDIR}${LIBDIR_BASE}/libroken.a
 LIBRPCSEC_GSS?=	${LIBDESTDIR}${LIBDIR_BASE}/librpcsec_gss.a
 LIBRPCSVC?=	${LIBDESTDIR}${LIBDIR_BASE}/librpcsvc.a
Index: share/mk/src.libnames.mk
===================================================================
--- share/mk/src.libnames.mk
+++ share/mk/src.libnames.mk
@@ -147,6 +147,7 @@
 		pthread \
 		radius \
 		readline \
+		regex \
 		roken \
 		rpcsec_gss \
 		rpcsvc \