I did it this way:
copy the default RA-controller-config to another place of your choice (i.e.: "/home/AMIBERRY Inputs/") edit the button-mapping as you like in this copied file start AMIBERRY-GUI go to "paths", navigate the "inputs"-path to your new one. click on the button "rescan paths" There you go, the inputs are now as you like to have them global for all games ;)