LWIP_HTTPD_CGI macro

Set this to 1 to support CGI (old style). This old style CGI support works by registering an array of URLs and associated CGI handler functions (http_set_cgi_handlers). This list is scanned just before fs_open is called from request handling. The handler can return a new URL that is used internally by the httpd to load the returned page (passed to fs_open). Use this CGI type e.g. to execute specific actions and return a page that does not depend on the CGI parameters.