Reverted INVALID_SUB/INVALID_DIR definitions to 16-bit due to too many ushort compares.

src/sbbs3/sbbsdefs.h

@@ -404,8 +404,8 @@ typedef enum {						/* Values for xtrn_t.event			*/
 #define CHAT_SPLITP (1<<4)	/* Split screen private chat				*/
 
 
-#define INVALID_DIR (~0)	/* Invalid directory value					*/
-#define INVALID_SUB (~0)	/* Invalid sub-board value					*/
+#define INVALID_DIR 0xffff	/* Invalid directory value					*/
+#define INVALID_SUB 0xffff	/* Invalid sub-board value					*/
 
 #define KEY_BUFSIZE 1024	/* Size of keyboard input buffer			*/
 #define SAVE_LINES	 4		/* Maximum number of lines to save			*/