Used for setting custom window shaders and rules for choosing custom
window shaders.
Added a "c2_userdata_free" parameter to c2_list_free, so allocated userdata
stored in nodes can be freed.
Signed-off-by: Bernd Busse <bernd@busse-net.de>
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
