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

6 files changed, 14 insertions, 26 deletions

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