Path::getPhysicalEncoding

static function getPhysicalEncoding()
{
	$physicalEncoding = defined("BX_FILE_SYSTEM_ENCODING") ? BX_FILE_SYSTEM_ENCODING : "";
	if ($physicalEncoding == "")
	{
		if (mb_strtoupper(mb_substr(PHP_OS, 0, 3)) === "WIN")
			$physicalEncoding = "windows-1251";
		else
			$physicalEncoding = "utf-8";
	}
	return mb_strtolower($physicalEncoding);
}