Description:
------------
No more received the signal HUP after using pcntl_exec

Test script:
---------------
#!/bin/php
<?php

function sig_handler()
{
    echo "sig_handler() called\n";
    pcntl_exec( "/test.php" );
}

echo "set signal\n";
pcntl_signal( SIGHUP, "sig_handler" );

while ( 1 ) {
  pcntl_signal_dispatch();
  sleep(1 );
}

?>

Expected result:
----------------
first kill -HUP PID
show :
sig_handler() called

do a second kill -HUP PID
and show :
sig_handler() called

Actual result:
--------------
first kill -HUP PID
show :
sig_handler() called

do a second kill -HUP PID
and nothing append and no more possible to do a CTRL+C on the program