busybox: add 1.18.0 runsvdir fix

diff -urpN busybox-1.18.0/runit/runsvdir.c busybox-1.18.0-runsvdir/runit/runsvdir.c

--- busybox-1.18.0/runit/runsvdir.c	2010-11-22 21:43:22.000000000 +0100

+++ busybox-1.18.0-runsvdir/runit/runsvdir.c	2010-12-06 01:27:56.926036992 +0100

@@ -312,8 +312,11 @@ int runsvdir_main(int argc UNUSED_PARAM,

 						last_mtime = s.st_mtime;

 						last_dev = s.st_dev;

 						last_ino = s.st_ino;

-						//if (now <= mtime)

-						//	sleep(1);

+						/* if the svdir changed this very second, wait until the

+						 * next second, because we won't be able to detect more

+						 * changes within this second */

+						while (time(NULL) == last_mtime)

+							usleep(100000);

 						need_rescan = do_rescan();

 						while (fchdir(curdir) == -1) {

 							warn2_cannot("change directory, pausing", "");