Fetches a symbol previously added to builder
with gtk_builder_add_callback_symbols()
This function is intended for possible use in language bindings
or for any case that one might be cusomizing signal connections
using gtk_builder_connect_signals_full()
Fetches a symbol previously added to builder with gtk_builder_add_callback_symbols() This function is intended for possible use in language bindings or for any case that one might be cusomizing signal connections using gtk_builder_connect_signals_full()