Support the "BCC self" option

libdelta.c

@@ -72,6 +72,12 @@ pwd_opt(const char *text, const char *name, const char *def)
 	return option;
 }
 
+static PurpleAccountOption *
+bool_opt(const char *text, const char *name, const gboolean def)
+{
+	return purple_account_option_bool_new(text, name, def);
+}
+
 static void
 delta_init_plugin(PurplePlugin *plugin)
 {
@@ -98,6 +104,8 @@ delta_init_plugin(PurplePlugin *plugin)
 	// Not exposed: server_flags, selfstatus, e2ee_enabled
 	// https://deltachat.github.io/api/classmrmailbox__t.html
 
+	opts = g_list_prepend(opts, bool_opt("Send copy to self", PLUGIN_ACCOUNT_OPT_BCC_SELF, FALSE));
+
 	extra->protocol_options = g_list_reverse(opts);
 }