Description:
------------
stream_set_blocking() simply doesn't work and block fgets function for retrieve data from stream

Test script:
---------------
<?php
$descriptorspec = array(
	0 => array("pipe", "r"),
	1 => array("pipe", "w")
);
$cwd = '/tmp';
$env = array();
$process = proc_open('uname -a', $descriptorspec, $pipes, $cwd, $env);
if(stream_set_blocking($pipes[1], false)){
echo "Success";
}else{
echo "Failed";
}
var_dump(stream_get_meta_data($pipes[1]));
$out = fgets ($pipes[1], 1024);
echo $out;
if(!$out){
	die("ERROR");
}
?>

Expected result:
----------------
Success
array(7) {
	["timed_out"]=> bool(false)
	["blocked"]=> bool(false)
	["eof"]=> bool(false)
	["stream_type"]=> string(5) "STDIO"
	["mode"]=> string(1) "r"
	["unread_bytes"]=> int(0)
	["seekable"]=> bool(false)
}
Linux riot 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Actual result:
--------------
Success
array(7) {
	["timed_out"]=> bool(false)
	["blocked"]=> bool(true)
	["eof"]=> bool(false)
	["stream_type"]=> string(5) "STDIO"
	["mode"]=> string(1) "r"
	["unread_bytes"]=> int(0)
	["seekable"]=> bool(false)
}
ERROR