apps/exmples/ostest:  Eliminate a warning.
/****************************************************************************
* apps/examples/ostest/ostest.h
*
- * Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
+ * Copyright (C) 2007-2009, 2011-2012, 2018 Gregory Nutt. All rights
+ * reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* see the output in context.
*/
+#ifndef CONFIG_STDIO_BUFFER_SIZE
+# define CONFIG_STDIO_BUFFER_SIZE 0
+#endif
+
#if CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0 && \
CONFIG_STDIO_BUFFER_SIZE > 0 && !defined(CONFIG_STDIO_LINEBUFFER)
# define FFLUSH() fflush(stdout)
