Make threads mandatory

G_THREADS_ENABLED still exists, but is always defined. It is still
possible to use libglib without threads, but gobject (and everything
above it) is now guaranteed to be using threads (as, in fact, it was
before, since it was accidentally impossible to compile with
--disable-threads).

https://bugzilla.gnome.org/show_bug.cgi?id=616754

glib/gmain.c

@@ -188,7 +188,6 @@ typedef enum
   G_SOURCE_CAN_RECURSE = 1 << (G_HOOK_FLAG_USER_SHIFT + 1)
 } GSourceFlags;
 
-#ifdef G_THREADS_ENABLED
 typedef struct _GMainWaiter GMainWaiter;
 
 struct _GMainWaiter
@@ -196,7 +195,6 @@ struct _GMainWaiter
   GCond *cond;
   GMutex *mutex;
 };
-#endif  
 
 typedef struct _GMainDispatch GMainDispatch;
 
@@ -212,7 +210,6 @@ gboolean _g_main_poll_debug = FALSE;
 
 struct _GMainContext
 {
-#ifdef G_THREADS_ENABLED
   /* The following lock is used for both the list of sources
    * and the list of poll records
    */
@@ -221,7 +218,6 @@ struct _GMainContext
   GThread *owner;
   guint owner_count;
   GSList *waiters;
-#endif  
 
   gint ref_count;
 
@@ -237,7 +233,6 @@ struct _GMainContext
   GPollFD *cached_poll_array;
   guint cached_poll_array_size;
 
-#ifdef G_THREADS_ENABLED
   GWakeup *wakeup;
 
   GPollFD wake_up_rec;
@@ -245,7 +240,6 @@ struct _GMainContext
 
 /* Flag indicating whether the set of fd's changed during a poll */
   gboolean poll_changed;
-#endif /* G_THREADS_ENABLED */
 
   GPollFunc poll_func;
 
@@ -312,15 +306,9 @@ struct _GSourcePrivate
   GSource *parent_source;
 };
 
-#ifdef G_THREADS_ENABLED
 #define LOCK_CONTEXT(context) g_static_mutex_lock (&context->mutex)
 #define UNLOCK_CONTEXT(context) g_static_mutex_unlock (&context->mutex)
 #define G_THREAD_SELF g_thread_self ()
-#else
-#define LOCK_CONTEXT(context) (void)0
-#define UNLOCK_CONTEXT(context) (void)0
-#define G_THREAD_SELF NULL
-#endif
 
 #define SOURCE_DESTROYED(source) (((source)->flags & G_HOOK_FLAG_ACTIVE) == 0)
 #define SOURCE_BLOCKED(source) (((source)->flags & G_HOOK_FLAG_IN_CALL) != 0 && \
@@ -515,16 +503,13 @@ g_main_context_unref (GMainContext *context)
       source = next;
     }
 
-#ifdef G_THREADS_ENABLED  
   g_static_mutex_free (&context->mutex);
-#endif
 
   g_ptr_array_free (context->pending_dispatches, TRUE);
   g_free (context->cached_poll_array);
 
   poll_rec_list_free (context, context->poll_records);
   
-#ifdef G_THREADS_ENABLED
   if (g_thread_supported())
     g_wakeup_free (context->wakeup);
 
@@ -534,12 +519,10 @@ g_main_context_unref (GMainContext *context)
 
   if (context->cond != NULL)
     g_cond_free (context->cond);
-#endif
 
   g_free (context);
 }
 
-#ifdef G_THREADS_ENABLED
 static void
 g_main_context_init_pipe (GMainContext *context)
 {
@@ -562,7 +545,6 @@ _g_main_thread_init (void)
   g_slist_free (main_contexts_without_pipe);
   main_contexts_without_pipe = NULL;  
 }
-#endif /* G_THREADS_ENABLED */
 
 /**
  * g_main_context_new:
@@ -589,12 +571,10 @@ g_main_context_new (void)
   }
 #endif
 
-#ifdef G_THREADS_ENABLED
   g_static_mutex_init (&context->mutex);
 
   context->owner = NULL;
   context->waiters = NULL;
-#endif
 
   context->ref_count = 1;
 
@@ -612,13 +592,11 @@ g_main_context_new (void)
   context->time_is_fresh = FALSE;
   context->real_time_is_fresh = FALSE;
   
-#ifdef G_THREADS_ENABLED
   if (g_thread_supported ())
     g_main_context_init_pipe (context);
   else
     main_contexts_without_pipe = g_slist_prepend (main_contexts_without_pipe, 
 						  context);
-#endif
 
   G_LOCK (main_context_list);
   main_context_list = g_slist_append (main_context_list, context);
@@ -955,10 +933,8 @@ g_source_attach (GSource      *source,
 
   result = g_source_attach_unlocked (source, context);
 
-#ifdef G_THREADS_ENABLED
   /* Now wake up the main loop if it is waiting in the poll() */
   g_main_context_wakeup_unlocked (context);
-#endif
 
   UNLOCK_CONTEXT (context);
 
@@ -2518,7 +2494,6 @@ next_valid_source (GMainContext *context,
 gboolean 
 g_main_context_acquire (GMainContext *context)
 {
-#ifdef G_THREADS_ENABLED
   gboolean result = FALSE;
   GThread *self = G_THREAD_SELF;
 
@@ -2542,9 +2517,6 @@ g_main_context_acquire (GMainContext *context)
   UNLOCK_CONTEXT (context); 
   
   return result;
-#else /* !G_THREADS_ENABLED */
-  return TRUE;
-#endif /* G_THREADS_ENABLED */
 }
 
 /**
@@ -2559,7 +2531,6 @@ g_main_context_acquire (GMainContext *context)
 void
 g_main_context_release (GMainContext *context)
 {
-#ifdef G_THREADS_ENABLED
   if (context == NULL)
     context = g_main_context_default ();
   
@@ -2588,7 +2559,6 @@ g_main_context_release (GMainContext *context)
     }
 
   UNLOCK_CONTEXT (context); 
-#endif /* G_THREADS_ENABLED */
 }
 
 /**
@@ -2611,7 +2581,6 @@ g_main_context_wait (GMainContext *context,
 		     GCond        *cond,
 		     GMutex       *mutex)
 {
-#ifdef G_THREADS_ENABLED
   gboolean result = FALSE;
   GThread *self = G_THREAD_SELF;
   gboolean loop_internal_waiter;
@@ -2658,9 +2627,6 @@ g_main_context_wait (GMainContext *context,
     UNLOCK_CONTEXT (context); 
   
   return result;
-#else /* !G_THREADS_ENABLED */
-  return TRUE;
-#endif /* G_THREADS_ENABLED */
 }
 
 /**
@@ -2700,7 +2666,6 @@ g_main_context_prepare (GMainContext *context,
       return FALSE;
     }
 
-#ifdef G_THREADS_ENABLED
   if (context->poll_waiting)
     {
       g_warning("g_main_context_prepare(): main loop already active in another thread");
@@ -2709,7 +2674,6 @@ g_main_context_prepare (GMainContext *context,
     }
   
   context->poll_waiting = TRUE;
-#endif /* G_THREADS_ENABLED */
 
 #if 0
   /* If recursing, finish up current dispatch, before starting over */
@@ -2855,9 +2819,7 @@ g_main_context_query (GMainContext *context,
       n_poll++;
     }
 
-#ifdef G_THREADS_ENABLED
   context->poll_changed = FALSE;
-#endif
   
   if (timeout)
     {
@@ -2907,7 +2869,6 @@ g_main_context_check (GMainContext *context,
       return FALSE;
     }
   
-#ifdef G_THREADS_ENABLED
   if (!context->poll_waiting)
     g_wakeup_acknowledge (context->wakeup);
 
@@ -2922,7 +2883,6 @@ g_main_context_check (GMainContext *context,
       UNLOCK_CONTEXT (context);
       return FALSE;
     }
-#endif /* G_THREADS_ENABLED */
   
   pollrec = context->poll_records;
   i = 0;
@@ -3029,7 +2989,6 @@ g_main_context_iterate (GMainContext *context,
 
   UNLOCK_CONTEXT (context);
 
-#ifdef G_THREADS_ENABLED
   if (!g_main_context_acquire (context))
     {
       gboolean got_ownership;
@@ -3053,7 +3012,6 @@ g_main_context_iterate (GMainContext *context,
     }
   else
     LOCK_CONTEXT (context);
-#endif /* G_THREADS_ENABLED */
   
   if (!context->cached_poll_array)
     {
@@ -3088,9 +3046,7 @@ g_main_context_iterate (GMainContext *context,
   if (dispatch)
     g_main_context_dispatch (context);
   
-#ifdef G_THREADS_ENABLED
   g_main_context_release (context);
-#endif /* G_THREADS_ENABLED */    
 
   LOCK_CONTEXT (context);
 
@@ -3241,7 +3197,6 @@ g_main_loop_run (GMainLoop *loop)
   g_return_if_fail (loop != NULL);
   g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0);
 
-#ifdef G_THREADS_ENABLED
   if (!g_main_context_acquire (loop->context))
     {
       gboolean got_ownership = FALSE;
@@ -3282,7 +3237,6 @@ g_main_loop_run (GMainLoop *loop)
     }
   else
     LOCK_CONTEXT (loop->context);
-#endif /* G_THREADS_ENABLED */ 
 
   if (loop->context->in_check_or_prepare)
     {
@@ -3298,9 +3252,7 @@ g_main_loop_run (GMainLoop *loop)
 
   UNLOCK_CONTEXT (loop->context);
   
-#ifdef G_THREADS_ENABLED
   g_main_context_release (loop->context);
-#endif /* G_THREADS_ENABLED */    
   
   g_main_loop_unref (loop);
 }
@@ -3325,10 +3277,8 @@ g_main_loop_quit (GMainLoop *loop)
   loop->is_running = FALSE;
   g_main_context_wakeup_unlocked (loop->context);
 
-#ifdef G_THREADS_ENABLED
   if (loop->context->cond)
     g_cond_broadcast (loop->context->cond);
-#endif /* G_THREADS_ENABLED */
 
   UNLOCK_CONTEXT (loop->context);
 }
@@ -3523,12 +3473,10 @@ g_main_context_add_poll_unlocked (GMainContext *context,
 
   context->n_poll_records++;
 
-#ifdef G_THREADS_ENABLED
   context->poll_changed = TRUE;
 
   /* Now wake up the main loop if it is waiting in the poll() */
   g_main_context_wakeup_unlocked (context);
-#endif
 }
 
 /**
@@ -3587,12 +3535,10 @@ g_main_context_remove_poll_unlocked (GMainContext *context,
       pollrec = nextrec;
     }
 
-#ifdef G_THREADS_ENABLED
   context->poll_changed = TRUE;
   
   /* Now wake up the main loop if it is waiting in the poll() */
   g_main_context_wakeup_unlocked (context);
-#endif
 }
 
 /**
@@ -3754,13 +3700,11 @@ _g_main_wake_up_all_contexts (void)
 static void
 g_main_context_wakeup_unlocked (GMainContext *context)
 {
-#ifdef G_THREADS_ENABLED
   if (g_thread_supported() && context->poll_waiting)
     {
       context->poll_waiting = FALSE;
       g_wakeup_signal (context->wakeup);
     }
-#endif
 }
 
 /**
@@ -3804,13 +3748,9 @@ g_main_context_is_owner (GMainContext *context)
   if (!context)
     context = g_main_context_default ();
 
-#ifdef G_THREADS_ENABLED
   LOCK_CONTEXT (context);
   is_owner = context->owner == G_THREAD_SELF;
   UNLOCK_CONTEXT (context);
-#else
-  is_owner = TRUE;
-#endif
 
   return is_owner;
 }