Description:
------------
Adding a bug for this so we can track it.

The leak size isn't constant even though the post data size in this example is constant, and the returned data (a dns error, presumably) is the same.  Seems like there is something weird in our postfield handling code in the curl extension.  Note also that it stabilizes somehow, although this is an extremely simplified version of a long-running command-line script that seems to grow on each post with wildly varying post data. 

Reproduce code:
---------------
<?php
function curl($post) {
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, "www.fdhfkdsslak.bogus");
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  if($post) {
    curl_setopt($ch, CURLOPT_POST, 1);
    for($args='',$i=0;$i<75;$i++) $args .= "a=$i&";
    curl_setopt($ch, CURLOPT_POSTFIELDS, $args);
    unset($args);
  }
  curl_exec($ch);
  curl_close($ch);
}
echo "start ".memory_get_usage()."\n";
for($i=0;$i<10;$i++) {
  curl(0);
  echo "GET ".memory_get_usage()."\n";
}
for($i=0;$i<10;$i++) {
  curl(1);
  echo "POST ".memory_get_usage()."\n";
}
?>


Expected result:
----------------
No memory_usage increase from one POST request to the next.

Actual result:
--------------
start 326616
GET 327256
GET 327276
GET 327276
GET 327276
GET 327276
GET 327276
GET 327276
GET 327276
GET 327276
GET 327276
POST 327516
POST 327588
POST 327652
POST 327712
POST 327892
POST 328064
POST 328228
POST 328384
POST 328528
POST 328628