With the new version 1.2.2 of RetroArch, I was motivated to investigate in RA override config files.This feature allows to have individual configurations such as button mappings for specific games. Very handy.
Here a configuration example for "Street Fighter III 3rd Strike" for the "FB Alpha" core with the same button mapping as in the first post.
1. Rename the attached config file "sfiii3.txt" to "sfiii3.cfg" and put it into directory "Internal Storage\Android\data\com.retroarch\files\FB Alpha", if RetroArch is installed in the internal storage.
2. Make sure the following options are configured in RA Settings -> Configuration.
3. Now, when you start SF III 3rd Strike, you should see the following (yellow) message.
Note: The attached config file also sets the video "Aspect Ratio Index" to "Core provided".
If you want the same config for other Street Fighter games, just copy "sfiii3.cfg" to the other game names like "sf2.cfg", "sf2ce.cfg", "ssf2.cfg" etc.
And of course, this method also works on other Android devices.
My main motivation was to use it on the Wii version of RA. Let me know if you're interested in such an example config file.