How to specify auto-generated resource files to Qmake?

http://doc.qt.io/qt-5/qmake-variable-reference.html

CONFIG+=lrelease #generates *.qm files from TRANSLATIONS= to the directory builddir/.qm/ CONFIG+=embed_translations #adds them as qrc resources

so (other than)

CONFIG+=lrelease embed_translations

no qmake magic is required. Your qm files will be under :/i18n/ unless you specify otherwise with

QM_FILES_RESOURCE_PREFIX=/my/customtranslationdirectory

Create the generated files in qmake phase with e.g. system(lrelease...). Leave the other rules in place too so you don't have to rerun qmake when the input files are changed.