Just a newline on the quit [confirm] prompt should not quit.

That is just too easy to type by accident. Only accept y, Y and EOF
(EOF for when there is an error).

src/klh10.c

@@ -599,11 +599,9 @@ fc_quit(struct cmd_s *cm)
     printf("Are you sure you want to quit? [Confirm]");
     fe_ctycmforce();
     switch (cminchar()) {
-    case '\r':
-    case '\n':
     case 'y':
     case 'Y':
-    case -1:		/* EOF */
+    case EOF:		/* EOF */
 	break;
     default:		/* Anything else prevents quit */
 	return;