* Don't generate our own marshallers if they are available in GLib
already
* Don't set the c_marshaller parameter in `g_signal_new()` if it's a
default marshaller provided by GLib. See commit message of commit
39e4aa3c57 on why this is the case.
Don't call gimp_input_device_store_lookup() with a NULL name. Unplug
seems broken because we always get name == NULL, I need to fix this
but at least it doesn't crash any longer (and the fix is generally
correct and not a workaround).