Fontconfig warning printed with fonctconfig 2.17

I'm on Arch Linux with Qt 6.9.1 and fontconfig 2.17, which was released recently.

Since this fontconfig upgrade, Qt applications are printing a warning at startup:

Fontconfig warning: using without calling FcInit()

This is reproducible with a minimal hello world Qt program:

#include <QApplication>
#include <QLabel>int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QLabel label("Hello World!");
    label.show();
    return app.exec();
}

This closed issue on fontconfig's issue tracker suggests downstream projects should adapt to this (presumably by calling a function called FcInit()):

https://gitlab.freedesktop.org/fontconfig/fontconfig/-/issues/472