commit 4111df1fe377787ffc6ff1fc0592fb3105f9ec81
Author: Kyle Evans <kevans@FreeBSD.org>
Date:   Thu Feb 18 08:39:32 2021 -0600

    sed: link against libregex for GNU extensions
    
    Applications like to use some GNU shorthand for common character
    classes, like \s and \S. This currently throws an error with sed(1) to
    point out their invalid usage, but would be hard to debug because
    grep(1) would happily accept them.
    
    Switch sed(1) over to using libregex as well.

diff --git a/usr.bin/sed/Makefile b/usr.bin/sed/Makefile
index 4cf4550801c..84881163451 100644
--- a/usr.bin/sed/Makefile
+++ b/usr.bin/sed/Makefile
@@ -7,6 +7,8 @@ PACKAGE=	runtime
 PROG=	sed
 SRCS=	compile.c main.c misc.c process.c
 
+LIBADD=	regex
+
 HAS_TESTS=
 SUBDIR.${MK_TESTS}+= tests