[virtualization][wine] Spoof a device as being the Steam Deck

[LukeShortCloud]

There are two ways to accomplish this:

• Launch Steam with the -steamdeck argument.
• Or set the launch options to a game in Steam to be SteamDeck=1 %command%".

This is required for games such as Forspoken.

https://www.gamingonlinux.com/2023/01/forspoken-desktop-linux-spoof-steam-deck/

[LukeShortCloud]

Valve now automatically sets the SteamDeck=1 variable for Forspoken so that workaround is no longer needed for the game.

https://steamdb.info/app/891390/history/?changeid=17495330

However, user reports that using SteamDeck=0 is needed for non Steam Deck devices to get better texture streaming performance.

https://www.protondb.com/app/1680880

[LukeShortCloud]

Related: https://github.com/LukeShortCloud/rootpages/issues/1002#issuecomment-1728156781