libbb: use <poll.h> instead of <sys/poll.h>

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

runit/runsvdir.c

@@ -35,7 +35,6 @@ ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 //usage:     "\n	-P		Put each runsv in a new session"
 //usage:     "\n	-s SCRIPT	Run SCRIPT <signo> after signal is processed"
 
-#include <sys/poll.h>
 #include <sys/file.h>
 #include "libbb.h"
 #include "runit_lib.h"