Description:
------------
if you (by accident, copy/paste, whatever) pass an argument
to get_include_path(), the function just returns an empty string, and NO diagnostic is issued. 

i've placed the reproduce script (with also a link generated to a phpinfo() call) at:

http://blog.lerctr.org/php_get_include_path_bug.php

the phpinfo() is at: 

http://blog.lerctr.org/php.php



Reproduce code:
---------------
<?php
  echo "get_include_path('include_path')=" . get_include_path('include_path');
  echo "<br>";
  echo "get_include_path()=" . get_include_path();
  echo "<br>";
?>


Expected result:
----------------
the bug is illustrated with the output of the first echo.

Actual result:
--------------
a diagnostic, or ignore the parameter, and return
the include_path.