Bug#908013: libindicator FTBFS with glib 2.58

[Adrian Bunk <bunk@debian.org>]

Source: libindicator
Version: 0.5.0-3
Severity: serious
Tags: ftbfs buster sid

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/libindicator.html

...
/build/1st/libindicator-0.5.0/./libindicator/indicator-object.c: In function 'indicator_object_class_init':
/build/1st/libindicator-0.5.0/./libindicator/indicator-object.c:131:2: error: 'g_type_class_add_private' is deprecated [-Werror=deprecated-declarations]
  g_type_class_add_private (klass, sizeof (IndicatorObjectPrivate));
  ^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/glib-2.0/gobject/gobject.h:24,
                 from /usr/include/glib-2.0/gobject/gbinding.h:29,
                 from /usr/include/glib-2.0/glib-object.h:23,
                 from /usr/include/glib-2.0/gio/gioenums.h:28,
                 from /usr/include/glib-2.0/gio/giotypes.h:28,
                 from /usr/include/glib-2.0/gio/gio.h:26,
                 from /usr/include/gtk-2.0/gdk/gdkapplaunchcontext.h:30,
                 from /usr/include/gtk-2.0/gdk/gdk.h:32,
                 from /usr/include/gtk-2.0/gtk/gtk.h:32,
                 from /build/1st/libindicator-0.5.0/./libindicator/indicator.h:26,
                 from /build/1st/libindicator-0.5.0/./libindicator/indicator-object.c:28:
/usr/include/glib-2.0/gobject/gtype.h:1303:10: note: declared here
 void     g_type_class_add_private       (gpointer                    g_class,
          ^~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[4]: *** [Makefile:643: libindicator_la-indicator-object.lo] Error 1