fix crash with lightning charge and plugin opts (#2358)

* fix crash with lightning charge and plugin opts

lightningd/options.c

@@ -1027,7 +1027,8 @@ static void add_config(struct lightningd *ld,
 		} else if (opt->cb_arg == (void *)opt_add_plugin) {
 			json_add_opt_plugins(response, ld->plugins);
 		} else if (opt->cb_arg == (void *)opt_add_plugin_dir
-			   || opt->cb_arg == (void *)opt_disable_plugin) {
+			   || opt->cb_arg == (void *)opt_disable_plugin
+			   || opt->cb_arg == (void *)plugin_opt_set) {
 			/* FIXME: We actually treat it as if they specified
 			 * --plugin for each one, so ignore these */
 #if DEVELOPER

lightningd/plugin.c

@@ -81,8 +81,6 @@ struct plugins {
 	struct lightningd *ld;
 };
 
-/* Simple storage for plugin options inbetween registering them on the
- * command line and passing them off to the plugin */
 struct plugin_opt {
 	struct list_node list;
 	const char *name;
@@ -463,9 +461,7 @@ static struct io_plan *plugin_stdout_conn_init(struct io_conn *conn,
 			       plugin_read_json, plugin);
 }
 
-/* Callback called when parsing options. It just stores the value in
- * the plugin_opt */
-static char *plugin_opt_set(const char *arg, struct plugin_opt *popt)
+char *plugin_opt_set(const char *arg, struct plugin_opt *popt)
 {
 	tal_free(popt->value);
 	popt->value = tal_strdup(popt, arg);

lightningd/plugin.h

@@ -18,6 +18,12 @@ struct plugins;
  */
 struct plugin;
 
+/**
+ * Simple storage for plugin options inbetween registering them on the
+ * command line and passing them off to the plugin
+ */
+struct plugin_opt;
+
 /**
  * Create a new plugins context.
  */
@@ -93,4 +99,10 @@ void plugins_notify(struct plugins *plugins,
 void plugin_request_send(struct plugin *plugin,
 			 struct jsonrpc_request *req TAKES);
 
+/**
+ * Callback called when parsing options. It just stores the value in
+ * the plugin_opt
+ */
+char *plugin_opt_set(const char *arg, struct plugin_opt *popt);
+
 #endif /* LIGHTNING_LIGHTNINGD_PLUGIN_H */