try to make time displayed approximately correct by synchronising
date-and-time update with minute roll-over.  currently it's a minute
late about half the time, on average.

Reference: /n/sources/patch/applied/faces-times
Date: Sun May  7 09:09:10 CES 2006
Signed-off-by: geoff@collyer.net

--- /sys/src/cmd/faces/main.c	Sun May  7 09:07:29 2006
+++ /sys/src/cmd/faces/main.c	Sun May  7 09:07:24 2006
@@ -150,7 +150,8 @@
 		updatetimes();
 		flushimage(display, 1);
 		unlockdisplay(display);
-		sleep(60000);
+		now = time(nil);
+		sleep(((60 - now%60) + 1)*1000); /* wait for minute to change */
 		setdate();
 	}
 }