Calculating the URL moniker (http vs https) on IIS with ISAPI

When using ISAPI on IIS, the PHP $_SERVER[HTTPS] variable is equal to the string "off" when accessing a site not made through the HTTPS protocol. See http://www.php.net/manual/en/reserved.variables.server.php

So to work on both ISS and Apache, line 75 in fblikebutton.module should be:

$http = (empty($_SERVER['HTTPS']) || ($_SERVER['HTTPS'] == 'off')) ? 'http://' : 'https://';