util-linux: Add fcntl-lock

Add a version of flock that uses the fnctl based lockf locking instead of
flock based locks. This allows us to take the same lock that opkg would
use from a shell script. The two different locking mechanisms operate
independently of each other.

Inserting this C file into the util-linux build seems like the easiest/best
place to insert the code. At this point it hasn't been discussed with upstream.

(From OE-Core rev: d2b784110e2c3df8a0a41e4819cf2de9003f9fa3)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/util-linux/util-linux_2.39.3.bb

@@ -147,6 +147,11 @@ SYSTEMD_AUTO_ENABLE:${PN}-uuidd = "disable"
 SYSTEMD_SERVICE:${PN}-fstrim = "fstrim.timer fstrim.service"
 SYSTEMD_AUTO_ENABLE:${PN}-fstrim = "disable"
 
+do_compile:append () {
+	cp ${WORKDIR}/fcntl-lock.c ${S}/fcntl-lock.c
+	${CC} ${CFLAGS} ${LDFLAGS} ${S}/fcntl-lock.c -o ${B}/fcntl-lock
+}
+
 do_install () {
 	# with ccache the timestamps on compiled files may
 	# end up earlier than on their inputs, this allows
@@ -182,6 +187,8 @@ do_install () {
 	echo 'MOUNTALL="-t nonfs,nosmbfs,noncpfs"' > ${D}${sysconfdir}/default/mountall
 
 	rm -f ${D}${bindir}/chkdupexe
+
+	install -m 0755 ${B}/fcntl-lock ${D}${bindir}
 }
 
 do_install:append:class-target () {