Match prototypes of callbacks with libgphoto

In ccc4c1f
we tried to fix by using pthread_t but it also needs to make changes in
libgphoto and these changes can be invasive, therefore lets revert to
older types and to fix musl problem fix it via type casts

Signed-off-by: Khem Raj <raj.khem@gmail.com>

gphoto2/main.c

@@ -1198,7 +1198,7 @@ thread_func (void *data)
 	pthread_cleanup_pop (1);
 }
 
-static pthread_t
+static unsigned int
 start_timeout_func (Camera *camera, unsigned int timeout,
 		    CameraTimeoutFunc func, void __unused__ *data)
 {
@@ -1215,14 +1215,14 @@ start_timeout_func (Camera *camera, unsigned int timeout,
 
 	pthread_create (&tid, NULL, thread_func, td);
 
-	return (tid);
+	return (unsigned int)tid;
 }
 
 static void
-stop_timeout_func (Camera __unused__ *camera, pthread_t id,
+stop_timeout_func (Camera __unused__ *camera, unsigned int id,
 		   void __unused__ *data)
 {
-	pthread_t tid = id;
+	pthread_t tid = (pthread_t)id;
 
 	pthread_cancel (tid);
 	pthread_join (tid, NULL);