Silence WARNS=2 and BDECFLAGS on alpha and i386

MFC After:	1 week

usr.bin/banner/Makefile

@@ -2,7 +2,8 @@
 # $FreeBSD$
 
 PROG=	banner
-CFLAGS+=-Wall
 MAN=	banner.6
 
+WARNS=	2
+
 .include <bsd.prog.mk>

usr.bin/banner/banner.c

@@ -1072,7 +1072,7 @@ main(int argc, char *argv[])
 		}
 		nchars = strlen(message);
 	} else {
-		if ((message = malloc(MAXMSG)) == NULL)
+		if ((message = malloc((size_t)MAXMSG)) == NULL)
 			err(1, "malloc");
 		fprintf(stderr,"Message: ");
 		(void)fgets(message, MAXMSG, stdin);