After commit https://git.gnome.org/browse/glib/commit/glib/glib-autocleanups.h?h=glib-2-46&id=d488d75909a7f5bdc13865a155ea583fcc3cb07f
in glib, mutter build fail.

In file included from /usr/include/glib-2.0/glib.h:110:0,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:23,
                 from /usr/include/cogl/cogl/cogl-types.h:44,
                 from /usr/include/cogl/cogl/cogl-error.h:36,
                 from /usr/include/cogl/cogl/cogl.h:64,
                 from ./backends/meta-monitor-manager-private.h:38,
                 from backends/x11/meta-monitor-manager-xrandr.h:26,
                 from backends/x11/meta-monitor-manager-xrandr.c:28:
backends/x11/meta-monitor-manager-xrandr.c: In function 'meta_monitor_manager_xrandr_read_current':
/usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: error: 'reply' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   g_free (*pp);
   ^
backends/x11/meta-monitor-manager-xrandr.c:336:55: note: 'reply' was declared here
   g_autofree xcb_randr_query_output_property_reply_t *reply;
                                                       ^
cc1: all warnings being treated as errors


I think, reply must be set to NULL.

mutter 3.18.2