We have a public symbol 'glib_on_error_halt' that is exported from
gbacktrace.c without appearing in a header, presumably with the
intention that people will be able to hit it from their debugger.
Mark it as GLIB_AVAILABLE_IN_ALL from inside the .c file...
https://bugzilla.gnome.org/show_bug.cgi?id=688681
static void stack_trace (char **args);
#endif
-extern volatile gboolean glib_on_error_halt;
+/* People want to hit this from their debugger... */
+GLIB_AVAILABLE_IN_ALL volatile gboolean glib_on_error_halt;
volatile gboolean glib_on_error_halt = TRUE;
/**