[mutter] clutter: Fix build with clang

[Marge Bot <marge-bot src gnome org>]

commit d439501faf68e8d7adac37ebca519ae832d85987
Author: Marc-Antoine Perennou <Marc-Antoine Perennou com>
Date:   Mon Jan 11 21:17:51 2021 +0100

    clutter: Fix build with clang
    
    Signed-off-by: Marc-Antoine Perennou <Marc-Antoine Perennou com>
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1668>

 clutter/clutter/cally/cally-text.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/clutter/clutter/cally/cally-text.c b/clutter/clutter/cally/cally-text.c
index c1419b4bfe..fe4abb710c 100644
--- a/clutter/clutter/cally/cally-text.c
+++ b/clutter/clutter/cally/cally-text.c
@@ -1866,7 +1866,7 @@ static gint
 _cally_atk_attribute_lookup_func (gconstpointer data,
                                   gconstpointer user_data)
 {
-    AtkTextAttribute attr = (AtkTextAttribute) user_data;
+    AtkTextAttribute attr = (AtkTextAttribute) GPOINTER_TO_INT (user_data);
     AtkAttribute *at = (AtkAttribute *) data;
     if (!g_strcmp0 (at->name, atk_text_attribute_get_name (attr)))
         return 0;