wrlib: new headers to contain definition of internal stuff

Using local function prototype redefinition is dangerous, now a single
prototype is seen in all the files that are concerned.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

wrlib/scale.h

@@ -0,0 +1,30 @@
+/*
+ * Raster graphics library
+ *
+ * Copyright (c) 2014 Window Maker Team
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library 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
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public
+ *  License along with this library.
+ */
+
+#ifndef WRASTER_SCALE_H
+#define WRASTER_SCALE_H
+
+
+/*
+ * Function to change the smoothing filter used for image scaling (RSmoothScaleImage)
+ */
+void wraster_change_filter(int type);
+
+
+#endif