# this function is for making a full Path that worked for me on windows:
defineReplace(fixPath) {
    rawPath = $$quote($$system_path($$absolute_path($$1)))
    return ($$rawPath)
}

    # This function creates the translation .qm files in DEPLOYMENTDIR/translation
    # @Param: List with all .ts files
    # @Param example: C://myapp/translations/exampleLanguage.ts
    defineReplace(createQMFiles){
        TRANSLATION_FILES = $$1

        fileNames =
        for(translationElement, TRANSLATION_FILES){
            rawTranslations = $$split(translationElement,/)
            file = $$last(rawTranslations)
            fileNames += $$file
        }

        fileNamesNoEnding =
        for(fileElement, fileNames){
            rawFileNameNoEnding = $$split(fileElement,.)
            fileNamesNoEnding += $$first(rawFileNameNoEnding)
        }

        QM_FILES =
        for(fileNameNoEnding,fileNamesNoEnding){
            QM_FILES += $$fixPath($$join(fileNameNoEnding, .qm, $${DEPLOYMENTDIR}/translations/, .qm))
        }

        LRELEASE = $$[QT_INSTALL_BINS]/lrelease #.exe

        NEW_TRANSLATIONS =
        for(entry, TRANSLATION_FILES){
            NEW_TRANSLATIONS += $$fixPath($$entry)
        }

        for(tsFile, NEW_TRANSLATIONS){
            command = $$LRELEASE $${tsFile} -qm $$take_first(QM_FILES)
            message($$command)
            system($$command)|error("Failed to run: $$command")
        }
        return
    }

I know that this is a really ugly way to do this. The "clean" way described in link did not work for me. Does anyone have a suggestion to do this in a cleaner way?

more information: I'm using QT version 5.9.7.