filter/Normalize: add normalize_filter_prepare()

src/filter/plugins/NormalizeFilterPlugin.cxx

@@ -18,6 +18,7 @@
  */
 
 #include "config.h"
+#include "NormalizeFilterPlugin.hxx"
 #include "filter/FilterPlugin.hxx"
 #include "filter/FilterInternal.hxx"
 #include "filter/FilterRegistry.hxx"
@@ -80,3 +81,9 @@ const FilterPlugin normalize_filter_plugin = {
 	"normalize",
 	normalize_filter_init,
 };
+
+PreparedFilter *
+normalize_filter_prepare() noexcept
+{
+	return new PreparedNormalizeFilter();
+}

src/filter/plugins/NormalizeFilterPlugin.hxx

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2003-2017 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_NORMALIZE_FILTER_PLUGIN_HXX
+#define MPD_NORMALIZE_FILTER_PLUGIN_HXX
+
+class PreparedFilter;
+class Filter;
+struct AudioFormat;
+
+PreparedFilter *
+normalize_filter_prepare() noexcept;
+
+#endif