Proxy the force-live and min-upstream-latency propertyies to the internal
glvideomixerelement at construction time. force-live has to be set
during construction of the glvideomixerelement, so that has to be
deferred until the _constructed() call. Make sure that all other
existing proxied properties will still get set once the element
is created.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4494>
Use the return value from gst_element_link_pads() and gst_bin_add()
Fixes:
../ext/gl/gstglmixerbin.c:305:12: error: variable 'res' set but not used [-Werror,-Wunused-but-set-variable]
gboolean res = TRUE;
^
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2038>