Description:
------------
Relative paths in require(), require_once(), include(), include_once() does not resolve correctly (i.e. relative to the file that reference the script, not the file that execute the script).

Reproduce code:
---------------
Say, there is the main script 'test.php' and two other files, 'a.inc'
and 'b.inc' (in subdirs):

File './test.php':
<?php
	require_once( 'include/a/a.inc' );
?>

File './include/a/a.inc':
<?php
	require_once( '../b.inc' );
	echo 'a.inc ';


?>

File './include/b.inc':
<?php
	echo 'b.inc ';
?>

Running 'test.php' fails.

Expected result:
----------------
When a.inc include "../b.inc", it should reference from the location of ./include/a/a.inc, not the executing file, ./test.php.

This happens on both Windows XP and UNIX (Red Hat Linux), and probably all other platforms (which I can't verify).

This really hurt modularity.

I know this is not consider a bug, but would you improve this please? (like adding a realtive_include() function would really be nice)

Actual result:
--------------
Fatal error: main() [function.require]: Failed opening required '../b.inc' (include_path='.;C:\php5\pear') in XXXXX on line 4