Some versions of Windows don't define LDAPS_PORT.

Also, Windows' ldap_sslinit() is documented to use LDAPS even if you
said secure=0 when the port number happens to be 636 or 3269.  Let's
avoid using the port number to imply that you want LDAPS, so that
connection strings have the same meaning on Windows and Unix.

Author: Thomas Munro
Discussion: https://postgr.es/m/CAEepm%3D23B7GV4AUz3MYH1TKpTv030VHxD2Sn%2BLYWDv8d-qWxww%40mail.gmail.com