public void set_allowed_backends (string backends)
Sets a list of backends that GDK should try to use.
This can be useful if your application does not work with certain GDK backends.
By default, GDK tries all included backends.
instructs GDK to try the Wayland backend first, followed by the Quartz backend, and then all others.
If the `GDK_BACKEND` environment variable is set, it determines what backends are tried in what order, while still respecting the set of allowed backends that are specified by this function.
The possible backend names are x11, win32, quartz, broadway, wayland. You can also include a * in the list to try all remaining backends.
a comma-separated list of backends