Description:
------------
My PHP is 5.2.13,if use under code
<?php
// Create a stream
$opts = array(
  'http'=>array(
    'method'=>"GET",
    'header'=>"Accept-language: en\r\n" .
              "Cookie: foo=bar\r\n"
  )
);

$context = stream_context_create($opts);

// Open the file using the HTTP headers set above
$file = file_get_contents('http://www.example.com/', false, $context);
?>

use Wireshark check HTTP request header is:
User-Agent: PHP/5.2.13\r\n
Host: en.wikipedia.org\r\n
Accept: */*\r\n

I set header not exists


Test script:
---------------
<?php
// Create a stream
$opts = array(
  'http'=>array(
    'method'=>"GET",
    'header'=>"Accept-language: en\r\n" .
              "Cookie: foo=bar\r\n"
  )
);

Expected result:
----------------
User-Agent: PHP/5.2.13\r\n
Host: en.wikipedia.org\r\n
Accept-language: en\r\n
Cookie: foo=bar\r\n

Actual result:
--------------
User-Agent: PHP/5.2.13\r\n
Host: en.wikipedia.org\r\n
Accept: */*\r\n