Can’t find answer anywhere...

[LunaMoo]

There are no ads in standard version nor any other difference outside of coloring and "buy gold" link between blue and gold, you might as well make yourself a PPSSPP purple, it's really just a color and exists as a form of donation mostly centered around android google play/app shop.

PPSSPP can be built for iOS, however the iOS port is regularly broken by iOS updates and doesn't have an active developer hence isn't officially supported. Also Apple doesn't want emulators in it's store as such there's really no motivation for gold version to even exist for it, it might even have negative motivation since some iOS users are already annoying enough spamming, requesting and demanding without giving them an option to become a "paying customer" and I seriously doubt Henrik would sacrifice his peace of mind for a few extra bucks ;o.

Anyway you can find build instructions here.

If you're iOS dev and want to contribute, instead of trying to provide gold version for it, IMHO you would be more helpful trying to solve iOS specific issues which you can find here.