Correct a few warnings that show upo in Clang but not in GCC

dbus/src/dbus_service.c

@@ -89,4 +89,5 @@ int start_dbus_service() {
   g_bus_own_name(G_BUS_TYPE_SYSTEM, "org.gnome.ShairportSync", G_BUS_NAME_OWNER_FLAGS_NONE, NULL,
                  on_name_acquired, NULL, NULL, NULL);
   //  G_BUS_TYPE_SESSION or G_BUS_TYPE_SYSTEM
+  return 0; // this is just to quieten a compiler warning
 }

dbus/src/shairport-sync-dbus-client.c

@@ -65,9 +65,10 @@ void *dbus_thread_func(void *arg) {
   g_main_loop_run(loop);
 
   //  dbus_service_main(); // let it run inside a thread
+  return NULL; // this is just to quieten a compiler warning.
 }
 
-void main(void) {
+int main(void) {
 
   pthread_create(&dbus_thread, NULL, &dbus_thread_func, NULL);
 
@@ -116,4 +117,6 @@ void main(void) {
   printf("exiting program.\n");
 
   g_object_unref(proxy);
+  
+  return 0;
 }

player.h

@@ -2,6 +2,7 @@
 #define _PLAYER_H
 
 #include <arpa/inet.h>
+#include <pthread.h>
 
 #include "config.h"
 

shairport.c

@@ -969,6 +969,7 @@ pthread_t dbus_thread;
 void *dbus_thread_func(void *arg) {
   loop = g_main_loop_new(NULL, FALSE);
   g_main_loop_run(loop);
+  return NULL;
 }
 #endif