glib: support return values and catching panics in spawn/spawn_local

Author: jf2048

glib/src/lib.rs

@@ -197,6 +197,7 @@ pub use self::bridged_logging::{rust_log_handler, GlibLogger, GlibLoggerDomain,
 pub mod subclass;
 
 mod main_context_futures;
+pub use main_context_futures::{JoinError, JoinHandle};
 mod source_futures;
 pub use self::source_futures::*;