Disable the optional libbsd fallback in favor of iproute2's own
strlcat/strlcpy routines. This prevents automagic linking and
all sorts of other related problems.

Bug: https://bugs.gentoo.org/911727
Signed-off-by: Holger Hoffstätte <holger@applied-asynchrony.com>

--- a/configure	2023-09-05 16:20:48.000000000 +0200
+++ b/configure	2023-09-05 16:29:15.850347415 +0200
@@ -454,14 +454,8 @@ EOF
     if $CC -I$INCLUDE -o $TMPDIR/strtest $TMPDIR/strtest.c >/dev/null 2>&1; then
 	echo "no"
     else
-	if ${PKG_CONFIG} libbsd --exists; then
-		echo 'HAVE_LIBBSD_CFLAGS += -DHAVE_LIBBSD' `${PKG_CONFIG} libbsd --cflags` >>$CONFIG
-		echo 'HAVE_LIBBSD_LDLIBS +=' `${PKG_CONFIG} libbsd --libs` >> $CONFIG
-		echo "no"
-	else
 		echo 'CFLAGS += -DNEED_STRLCPY' >>$CONFIG
 		echo "yes"
-	fi
     fi
     rm -f $TMPDIR/strtest.c $TMPDIR/strtest
 }