This is for the various Commodore systems.

NOTE:

Make sure that in retroarch-core-options.cfg you have these settings:

vice_Statusbar = "disabled"
vice_Drive8Type = "1541"
vice_DriveTrueEmulation = "enabled"
vice_RetroJoy = "disabled"
vice_Controller = "keyboard" 

Settings taken from here (dated March 2017, so it may no longer be relevant):
https://forums.launchbox-app.com/topic/37059-retroarch-and-commoroe-64-3-new-cores-3rd-one-vice-30-commodore-64-emulator/?tab=comments#comment-233323