hide output of etags

even the message "sh: etags: not such file or directory" or whatever
seems to be confusing for users, so silent it.

(maybe it would be better not to automatically generate the TAGS, but
it's so handy...)

Makefile

@@ -26,7 +26,7 @@ static: ${OBJS}
 	${CC} ${OBJS} -o gmid ${LDFLAGS} ${STATIC}
 
 TAGS: ${SRCS}
-	-etags ${SRCS} || true
+	@(etags ${SRCS} || true) 2>/dev/null
 
 clean:
 	rm -f *.o compat/*.o lex.yy.c y.tab.c y.tab.h y.output gmid gg