*: use {i,u}toa() where appropriate

function                                             old     new   delta
startservice                                         377     363     -14
setari_u                                              54      40     -14
ash_main                                            1375    1361     -14
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-42)             Total: -42 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/cal.c b/coreutils/cal.c
index 9b59777..ef70b0e 100644
--- a/coreutils/cal.c
+++ b/coreutils/cal.c
@@ -147,7 +147,7 @@
 		unsigned *dp;
 		char lineout[80];
 
-		sprintf(lineout, "%d", year);
+		sprintf(lineout, "%u", year);
 		center(lineout,
 			   (WEEK_LEN * 3 + HEAD_SEP * 2)
 			   + julian * (J_WEEK_LEN * 2 + HEAD_SEP