Description:
------------
ob_start(ob_gzhandler) can be used to send optionally compressed-output to clients.

But the test made to check whether the client supports gzip/deflate encoding only looks at the appearance of the string "gzip" (resp. "deflate") in the Accept-Encoding header, but doesn't actually parse the said header.

This means that the following Accept-Encoding headers will trigger generation of gzip-compressed output when they should not:
* using a string with gzip in it 
Accept-Encoding: foogzip25
* using quality parameters as made possible in HTTP
Accept-Encoding: gzip;q=0, identity;q=1 


Test script:
---------------
<?php
if (!ob_start("ob_gzhandler")) {
  ob_start();
  echo "Uncompressed";
} else {
  echo "Compressed";
}
ob_end_flush();
?>

Expected result:
----------------
The script below can be used to test with the accept-encoding reported above; the said accept-encoding should report "Uncompressed" but reports "Compressed" (gzipped).