Example: mouse

The host device mapped to Amiga joystick port 0. If not specified, a suitable
device is automatically chosen depending on [joystick_port_0_mode] (usually
a mouse). Valid values:

* mouse
* keyboard
* name of connected game pad or joystick
* nothing

See also [joystick_port_0_mode], [joystick_port_0_autofire].
