Fix -Werror=cast-function-type

Bump glib-2 required version to 2.58:

  G_SOURCE_FUNC

  https://gitlab.gnome.org/GNOME/glib/commit/039fa6897bb4c5cd30caec8ee3add1a4ef612f76

Build & install:i

  export CC=gcci
  export CFLAGS=-Werror=cast-function-type
  ./autogen.sh --prefix=/usr
  make clean
  make
  sudo make install

10 files changed, 41 insertions, 35 deletions

diff --git a/configure.ac b/configure.ac
index 106bc60f..fc1a6288 100644
--- a/configure.ac
+++ b/configure.ac
@@ -155,7 +155,7 @@ AC_CHECK_HEADERS(execinfo.h, [AC_CHECK_FUNCS(backtrace)])
 
 AM_GLIB_GNU_GETTEXT
 
-PKG_CHECK_MODULES(ALL, glib-2.0 >= 2.50.0)
+PKG_CHECK_MODULES(ALL, glib-2.0 >= 2.58.0)
 PKG_CHECK_MODULES(MARCO_MESSAGE, gtk+-3.0 >= $GTK_MIN_VERSION)
 PKG_CHECK_MODULES(MARCO_WINDOW_DEMO, gtk+-3.0 >= $GTK_MIN_VERSION)
 
diff --git a/src/core/boxes.c b/src/core/boxes.c
index c36abfcd..c9ce916a 100644
--- a/src/core/boxes.c
+++ b/src/core/boxes.c
@@ -767,10 +767,7 @@ meta_rectangle_expand_to_avoiding_struts (MetaRectangle       *rect,
 void
 meta_rectangle_free_list_and_elements (GList *filled_list)
 {
-  g_list_foreach (filled_list,
-                  (void (*)(gpointer,gpointer))&g_free, /* ew, for ugly */
-                  NULL);
-  g_list_free (filled_list);
+  g_list_free_full (filled_list, g_free);
 }
 
 gboolean
diff --git a/src/core/edge-resistance.c b/src/core/edge-resistance.c
index 8a0d1854..d8a643a6 100644
--- a/src/core/edge-resistance.c
+++ b/src/core/edge-resistance.c
@@ -1105,13 +1105,7 @@ compute_resistance_and_snapping_edges (MetaDisplay *display)
   g_list_free (stacked_windows);
   /* Free the memory used by the obscuring windows/docks lists */
   g_slist_free (window_stacking);
-  /* FIXME: Shouldn't there be a helper function to make this one line of code
-   * to free a list instead of four ugly ones?
-   */
-  g_slist_foreach (obscuring_windows,
-                   (void (*)(gpointer,gpointer))&g_free, /* ew, for ugly */
-                   NULL);
-  g_slist_free (obscuring_windows);
+  g_slist_free_full (obscuring_windows, g_free);
 
   /* Sort the list.  FIXME: Should I bother with this sorting?  I just
    * sort again later in cache_edges() anyway...
diff --git a/src/core/eventqueue.c b/src/core/eventqueue.c
index 290f9543..c85fdc51 100644
--- a/src/core/eventqueue.c
+++ b/src/core/eventqueue.c
@@ -22,6 +22,7 @@
  * 02110-1301, USA.  */
 
 #include "eventqueue.h"
+#include <glib-object.h>
 #include <X11/Xlib.h>
 
 static gboolean eq_prepare  (GSource     *source,
@@ -70,7 +71,7 @@ meta_event_queue_new (Display *display, MetaEventQueueFunc func, gpointer data)
   g_source_add_poll (source, &eq->poll_fd);
   g_source_set_can_recurse (source, TRUE);
 
-  g_source_set_callback (source, (GSourceFunc) func, data, NULL);
+  g_source_set_callback (source, G_SOURCE_FUNC (func), data, NULL);
 
   g_source_attach (source, NULL);
   g_source_unref (source);
@@ -152,7 +153,7 @@ eq_dispatch (GSource *source, GSourceFunc callback, gpointer user_data)
       MetaEventQueueFunc func;
 
       event = g_queue_pop_head (eq->events);
-      func = (MetaEventQueueFunc) callback;
+      func = (MetaEventQueueFunc) G_CALLBACK (callback);
 
       (* func) (event, user_data);
 
diff --git a/src/core/main.c b/src/core/main.c
index 31958d22..6f6170d6 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -385,7 +385,9 @@ sigterm_handler (int signum)
 }
 
 static gboolean
-on_sigterm (void)
+on_sigterm (GIOChannel   *source,
+            GIOCondition condition,
+            gpointer     user_data)
 {
   meta_quit (META_EXIT_SUCCESS);
   return FALSE;
@@ -437,7 +439,7 @@ main (int argc, char **argv)
 
   channel = g_io_channel_unix_new (sigterm_pipe_fds[0]);
   g_io_channel_set_flags (channel, G_IO_FLAG_NONBLOCK, NULL);
-  g_io_add_watch (channel, G_IO_IN, (GIOFunc) on_sigterm, NULL);
+  g_io_add_watch (channel, G_IO_IN, on_sigterm, NULL);
   g_io_channel_set_close_on_unref (channel, TRUE);
   g_io_channel_unref (channel);
 
diff --git a/src/core/screen.c b/src/core/screen.c
index 0b79c460..e14f8d52 100644
--- a/src/core/screen.c
+++ b/src/core/screen.c
@@ -648,9 +648,8 @@ meta_screen_free (MetaScreen *screen,
   meta_screen_ungrab_keys (screen);
 
 #ifdef HAVE_STARTUP_NOTIFICATION
-  g_slist_foreach (screen->startup_sequences,
-                   (GFunc) sn_startup_sequence_unref, NULL);
-  g_slist_free (screen->startup_sequences);
+  g_slist_free_full (screen->startup_sequences,
+                     (GDestroyNotify) sn_startup_sequence_unref);
   screen->startup_sequences = NULL;
 
   if (screen->startup_sequence_timeout != 0)
@@ -797,8 +796,7 @@ meta_screen_manage_all_windows (MetaScreen *screen)
     }
   meta_stack_thaw (screen->stack);
 
-  g_list_foreach (windows, (GFunc)g_free, NULL);
-  g_list_free (windows);
+  g_list_free_full (windows, g_free);
 
   meta_display_ungrab (screen->display);
 }
@@ -838,8 +836,7 @@ meta_screen_composite_all_windows (MetaScreen *screen)
 
   meta_stack_thaw (screen->stack);
 
-  g_list_foreach (windows, (GFunc)g_free, NULL);
-  g_list_free (windows);
+  g_list_free_full (windows, g_free);
 #endif
 }
 
diff --git a/src/core/util.c b/src/core/util.c
index a30707a7..7b5f0803 100644
--- a/src/core/util.c
+++ b/src/core/util.c
@@ -207,10 +207,7 @@ utf8_fputs (const char *str,
 void
 meta_free_gslist_and_elements (GSList *list_to_deep_free)
 {
-  g_slist_foreach (list_to_deep_free,
-                   (void (*)(gpointer,gpointer))&g_free, /* ew, for ugly */
-                   NULL);
-  g_slist_free (list_to_deep_free);
+  g_slist_free_full (list_to_deep_free, g_free);
 }
 
 #ifdef WITH_VERBOSE_MODE
diff --git a/src/ui/menu.c b/src/ui/menu.c
index aeba64fa..90db5f1e 100644
--- a/src/ui/menu.c
+++ b/src/ui/menu.c
@@ -100,6 +100,21 @@ static MenuItem menuitems[] = {
 	{META_MENU_OP_DELETE, MENU_ITEM_IMAGE, MARCO_STOCK_DELETE, FALSE, N_("_Close")}
 };
 
+static void
+sn_menu_data_free (MenuData *menu_data,
+                   GClosure *closure)
+{
+  g_free (menu_data->menu);
+  g_free (menu_data);
+}
+
+static void
+sn_menu_item_free (MenuItem *menu_item,
+                   GClosure *closure)
+{
+  g_free (menu_item);
+}
+
 static void popup_position_func(GtkMenu* menu, gint* x, gint* y, gboolean* push_in, gpointer user_data)
 {
 	GtkRequisition req;
@@ -442,7 +457,7 @@ meta_window_menu_new   (MetaFrames         *frames,
                           "activate",
                           G_CALLBACK (activate_cb),
                           md,
-                          (GClosureNotify) g_free, 0);
+                          (GClosureNotify) sn_menu_data_free, 0);
 
                       gtk_menu_shell_append (GTK_MENU_SHELL (submenu), submi);
 
@@ -469,7 +484,7 @@ meta_window_menu_new   (MetaFrames         *frames,
                                      "activate",
                                      G_CALLBACK (activate_cb),
                                      md,
-                                     (GClosureNotify) g_free, 0);
+                                     (GClosureNotify) sn_menu_item_free, 0);
             }
 
           if (mi)
diff --git a/src/ui/tabpopup.c b/src/ui/tabpopup.c
index 37231a5b..10c7898f 100644
--- a/src/ui/tabpopup.c
+++ b/src/ui/tabpopup.c
@@ -636,7 +636,9 @@ unselect_image (GtkWidget *widget)
   gtk_widget_queue_draw (widget);
 }
 
-static void     meta_select_image_class_init   (MetaSelectImageClass *klass);
+static void     meta_select_image_class_init   (MetaSelectImageClass *klass,
+                                                void                 *data);
+
 static gboolean meta_select_image_draw         (GtkWidget            *widget,
                                                 cairo_t              *cr);
 
@@ -669,7 +671,7 @@ meta_select_image_get_type (void)
 }
 
 static void
-meta_select_image_class_init (MetaSelectImageClass *klass)
+meta_select_image_class_init (MetaSelectImageClass *klass, void *data)
 {
   GtkWidgetClass *widget_class;
 
@@ -805,7 +807,8 @@ unselect_workspace (GtkWidget *widget)
   gtk_widget_queue_draw (widget);
 }
 
-static void meta_select_workspace_class_init (MetaSelectWorkspaceClass *klass);
+static void meta_select_workspace_class_init (MetaSelectWorkspaceClass *klass,
+                                              void                     *data);
 
 static gboolean meta_select_workspace_draw (GtkWidget *widget,
                                             cairo_t   *cr);
@@ -840,7 +843,8 @@ meta_select_workspace_get_type (void)
 }
 
 static void
-meta_select_workspace_class_init (MetaSelectWorkspaceClass *klass)
+meta_select_workspace_class_init (MetaSelectWorkspaceClass *klass,
+                                  void                     *data)
 {
   GtkWidgetClass *widget_class;
 
diff --git a/src/wm-tester/main.c b/src/wm-tester/main.c
index 1581f666..d45b09f7 100644
--- a/src/wm-tester/main.c
+++ b/src/wm-tester/main.c
@@ -230,8 +230,7 @@ set_up_icon_windows (void)
 
       gtk_window_set_icon_list (GTK_WINDOW (w), icons);
 
-      g_list_foreach (icons, (GFunc) g_object_unref, NULL);
-      g_list_free (icons);
+      g_list_free_full (icons, g_object_unref);
 
       gtk_widget_show_all (w);