Part of bug 644353, patch by Ulrik Sverdrup.
/**
* gtk_accelerator_parse:
* @accelerator: string representing an accelerator
- * @accelerator_key: (out): return location for accelerator keyval
- * @accelerator_mods: (out): return location for accelerator modifier mask
+ * @accelerator_key: (out) (allow-none): return location for accelerator
+ * keyval, or %NULL
+ * @accelerator_mods: (out) (allow-none): return location for accelerator
+ * modifier mask, %NULL
*
* Parses a string representing an accelerator. The
* format looks like "<Control>a" or "<Shift><Alt>F1"