Description:
------------
fread() fails (core dumps) for ssh2 streams.

I have checked the libssh2 library by writing a small C program, and it seems to handle non-blocking channels correct.

The stream read command (libssh2_channel_read_ex) does return -37 for non-blocking channels where there are no pending bytes. This "error" might be reason for the core dump? 

Not sure if the correct place to fix this is in the fread() function or the php_ssh2_channel_stream_read() function by preventing it from returning a negative number (libssh2).

The ssh2 pecl package does not compile under php 5.3 (I belive this is a error in the package and not in php-headers - I've managed to fix this though, so it does compile)


Reproduce code:
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#!/usr/bin/php
<?php

$connection = ssh2_connect(SERVER_NAME, 22, array('hostkey'=>'ssh-rsa'));
if(ssh2_auth_pubkey_file($connection, USERNAME, ID_PUB, ID_RSA, '')) {
   $stream = ssh2_exec($connection, "ps -elf");
   # stream_set_blocking($stream, false); THIS DOSN'T WORK
   stream_set_blocking($stream, true); // THIS WORKS

   while(!feof($stream)) {
      $buf = fread($stream, 1024);
      echo ">$buf\n";
   }
}

?>

Expected result:
----------------
No core dump

Actual result:
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Core dump