-# ifndef PARAMS
-# if defined PROTOTYPES || (defined __STDC__ && __STDC__)
-# define PARAMS(Args) Args
-# else
-# define PARAMS(Args) ()
-# endif
+# include <stddef.h>
+
+# ifndef DIRECTORY_SEPARATOR
+# define DIRECTORY_SEPARATOR '/'
+# endif
+
+# ifndef ISSLASH
+# define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
+# endif
+
+# ifndef FILESYSTEM_PREFIX_LEN
+# define FILESYSTEM_PREFIX_LEN(Filename) 0