Description:
------------
pcntl_signal is not executing the code inside the function handling of the signal. The code example is taken from the php manual in http://www.php.net/manual/en/ref.pcntl.php and modified just to echo a simple text

Reproduce code:
---------------
<?php
declare(ticks=1);

$pid = pcntl_fork();
if ($pid == -1) {
     die("could not fork"); 
} else if ($pid) {
     exit(); // we are the parent 
} else {
     // we are the child
}

if (!posix_setsid()) {
   die("could not detach from terminal");
}

while (1) {
   // do something interesting here
}

function sig_handler($signo) 
{
     switch ($signo) {
         case SIGTERM:
             // handle shutdown tasks
             echo "I need to execute\n";
             exit;
             break;
         case SIGHUP:
             // handle restart tasks
             break;
         default:
             // handle all other signals
     }

}

// setup signal handlers
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGHUP, "sig_handler");
?> 

Expected result:
----------------
When you send the signal SIGTERM with kill -15 PID the process should echo the message "I need to execute" and then terminate.

Actual result:
--------------
The process terminate but doesn't echo or execute anything inside the function handler.