Simplify yes(1)

Just pick the first argument if multiple are provided.

yes.c

@@ -8,24 +8,13 @@ static void usage(void);
 int
 main(int argc, char *argv[])
 {
-	char *s = "y";
-
 	ARGBEGIN {
 	default:
 		usage();
 	} ARGEND;
 
-	switch(argc) {
-	case 1:
-		s = argv[0];
-		/* fallthrough */
-	case 0:
 	for (;;)
-			puts(s);
-		break;
-	default:
-		usage();
-	}
+		puts(argc >= 1 ? argv[0] : "y");
 	return EXIT_FAILURE; /* should not reach */
 }