When PHP compiled as CGI for Apache - POST variables don't set.

./configure --prefix=/usr --with-config-file-path=/etc/httpd/conf --enable-force-cgi-redirect --with-mysql=/usr/local --with-gd --with-pgsql=/usr

I cannot access to it by $_POST['field_name'] or $HTTP_POST_VARS['field_name'] or $field_name.

Script example
index.php --------------------

<?php
print $HTTP_POST_VARS['username']."<br>";
print $_POST['username']."<br>";
print $username."<br>";
?>

<form action="index.php" method="POST">
<input type="text" name="username" value="alex">
<input type="submit" value="Send">
</form>