initialize GError pointers

src/decoder_thread.c

@@ -253,7 +253,7 @@ static gpointer decoder_task(G_GNUC_UNUSED gpointer arg)
 
 void decoder_thread_start(void)
 {
-	GError *e;
+	GError *e = NULL;
 	GThread *t;
 
 	if (!(t = g_thread_create(decoder_task, NULL, FALSE, &e)))

src/output_thread.c

@@ -167,7 +167,7 @@ static gpointer audio_output_task(gpointer arg)
 
 void audio_output_thread_start(struct audio_output *ao)
 {
-	GError *e;
+	GError *e = NULL;
 
 	assert(ao->command == AO_COMMAND_NONE);
 

src/player_thread.c

@@ -556,7 +556,7 @@ static gpointer player_task(G_GNUC_UNUSED gpointer arg)
 
 void player_create(void)
 {
-	GError *e;
+	GError *e = NULL;
 	GThread *t;
 
 	if (!(t = g_thread_create(player_task, NULL, FALSE, &e)))

src/update.c

@@ -653,7 +653,7 @@ static void * update_task(void *_path)
 
 static void spawn_update_task(char *path)
 {
-	GError *e;
+	GError *e = NULL;
 
 	assert(g_thread_self() == main_task);