Ionic component adaptations gone after --prod build


I made some adaptations to the source of the ionic components in \node_modules\ionic-angular\components; added a property to the ActionSheetOptions, used it in the template, enabled usage of html in the ToastController…

All of these adaptations are gone when using the prod build, they are present in a debug build.

What is the reason for this?
And, most important, how to fix this?