IsGame()

         Indicates if the system has joystick

    Syntax:

         IsGame() -> lExist

    Description:

         Determines if the system has a joystick adapting or emulating
         if this is enough intelligent to actualize the BIOS communications
         area.

    Return:

         .T. if there's joystick and .f. if there isn't

    Example:

         If IsJoystick()
           Warning ( "My computer is a gameboy" )
         EndIf