Description:
------------
I recently upgraded to php 5.0.2 from 4.3.9.
The array that is input into array_count_values, is being 
modified.
Under 4.3.9, this function worked as expected.

Reproduce code:
---------------
<?php

header('content-type: text/plain');

$foo = array('abc', '0000');
var_export($foo);

echo "\n\n";

$count = array_count_values( $foo );
var_export($count);

echo "\n\n";

var_export($foo);

?>

Expected result:
----------------
array (
  0 => 'abc',
  1 => '0000',
)

array (
  'abc' => 1,
  '0000' => 1,
)

array (
  0 => 'abc',
  1 => '0000',
)

Actual result:
--------------
array (
  0 => 'abc',
  1 => '0000',
)

array (
  'abc' => 1,
  0 => 1,
)

array (
  0 => 'abc',
  1 => 0,
)