Expand the -r option to support hex. Though undocumented, the -r

option already supported octal. Add a comment to the -r option
in the man page so it's a bit more specific.

Discrepancy brought to my attention by: sasdrq@unx.sas.com
Approved by:	jkh

bin/date/date.1

@@ -122,7 +122,7 @@ is the number of seconds since the Epoch
 00:00:00 UTC, January 1, 1970;
 see
 .Xr time 3
-.Pc .
+.Pc and can be specified in decimal, octal, or hex.
 .It Fl t Ar minutes_west
 Set the system's value for minutes west of
 .Tn GMT .

bin/date/date.c

@@ -116,7 +116,8 @@ main(argc, argv)
 			break;
 		case 'r':		/* user specified seconds */
 			rflag = 1;
-			tval = atol(optarg);
+			if (sscanf(optarg,"%li",&tval) != 1)
+				usage();
 			break;
 		case 't':		/* minutes west of UTC */
 					/* error check; don't allow "PST" */