After building zxid, cd to zxid directory and run
mini_httpd -p 8443 -c 'zxid*' -S -E zxid.pem
where
-p 8443 specifies the port to listen to -c 'zxid*' specifies that URL paths with "zxid" are CGI scripts -S specifies that https is to be used -E zxid.pem specifies the SSL certificate to use
See Apache recipe for alternative that avoids mini_httpd, but is more complicated otherwise.
N.B. The zxid.pem certificate and private key combo is shipped with zxid for demonstration purposes. Obviously everybody who downloads zxid has that private key, so there is no real security what-so-ever. For production use, you must generate, or acquire, your own private key-certificate pair (and keep the private key secret). See Certificates chapter for further info.