The Qt allow for flexible workflow for developing application with internationalization support since a lot depends on nature of the project and team dynamics.

The only extra call needed in CMakeList.txt is qt_add_translations which will add build targets update_translations (updates content of *.ts files for sources) and *release_translations (*generates *.qm files). How you will use those targets is up to you. Some may would like to add them to default build but please notice that in most cases it's not necessary. You need to make decision based on needs of your project and your team.

Alternatively to calling qt_add_translations you can choose to initialize internationalization using qt_standard_project_setup. Again build targets are produced for you and you decide on the workflow.

Here is an example of one of many of possible workflows:
1. Code is being developed and tested using default cmake build target (all)
2. If there were some changes to strings for translations you can update ts files by running build target update_translations How frequent will you do it is totally up to you e.g. you can do it just once, before doing the translations
3. Whenever translations (*.ts files) were updated you can generate *.qm files by running build target release_translations. Subsequent build of application will use updated files assuming application has default settings (*.qm files being included in application resources).

If you are using Qt Creator as your IDE you can simply switch build targets for cmake with few mouse clicks - you need to open details of build step (Projects view) and select/deselect desired targets on list.