Add the G_OPTION_ENTRY_NULL macro to properly initialize GOptionEntry arrays

docs/reference/glib/glib-sections.txt

@@ -1649,6 +1649,7 @@ GOptionArg
 GOptionFlags
 G_OPTION_REMAINING
 GOptionEntry
+G_OPTION_ENTRY_NULL
 g_option_context_add_main_entries
 GOptionGroup
 g_option_context_add_group

glib/goption.c

@@ -102,7 +102,7 @@
  *   { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose, "Be verbose", NULL },
  *   { "beep", 'b', 0, G_OPTION_ARG_NONE, &beep, "Beep when done", NULL },
  *   { "rand", 0, 0, G_OPTION_ARG_NONE, &randomize, "Randomize the data", NULL },
- *   { NULL }
+ *   G_OPTION_ENTRY_NULL
  * };
  *
  * int

glib/goption.h

@@ -286,6 +286,24 @@ struct _GOptionEntry
  */
 #define G_OPTION_REMAINING ""
 
+/**
+ * G_OPTION_ENTRY_NULL:
+ *
+ * A #GOptionEntry array requires a %NULL terminator, this macro can
+ * be used as terminator instead of an explicit `{ 0 }` but it cannot
+ * be assigned to a variable.
+ *
+ * |[
+ *   GOptionEntry option[] = { G_OPTION_ENTRY_NULL };
+ * ]|
+ *
+ * Since: 2.70
+ */
+#define G_OPTION_ENTRY_NULL    \
+  GLIB_AVAILABLE_MACRO_IN_2_70 \
+  { NULL, 0, 0, 0, NULL, NULL, NULL }
+
+
 GLIB_AVAILABLE_IN_ALL
 GOptionContext *g_option_context_new              (const gchar         *parameter_string);
 GLIB_AVAILABLE_IN_ALL