Description:
------------
If you try to convert one character set into the same character set using this function, it causes a 500 internal server error that shows up in the logs as:

[error] [client XXX.XXX.XXX.XXX] Premature end of script headers: myscript.php

Reproduce code:
---------------
$charset = "ISO-8859-1";

try {
  $i= iconv($charset, "ISO-8859-1", "123321ksdjvskjdfksdfbasbdaSDjhdb");
  echo $i;
  } 
catch (Exception $e) {
echo 'Caught exception: ',  $e->getMessage(), "\n";	
}


Expected result:
----------------
123321ksdjvskjdfksdfbasbdaSDjhdb

Actual result:
--------------
500 Internal Server Error