Apache part - enabling you to open https://localhost/xyz
There is the config file xampp/apache/conf/extra/httpd-ssl.conf which contains all the ssl specific configuration. It's fairly well documented, so have a read of the comments and take look at http://httpd.apache.org/docs/2.2/ssl/.
The files starts with <IfModule ssl_module>
, so it only has an effect if the apache has been started with its mod_ssl module.
Open the file xampp/apache/conf/httpd.conf in an editor and search for the line
#LoadModule ssl_module modules/mod_ssl.so
remove the hashmark, save the file and re-start the apache. The webserver should now start with xampp's basic/default ssl confguration; good enough for testing but you might want to read up a bit more about mod_ssl in the apache documentation.
PHP part - enabling adldap to use ldap over ssl
adldap needs php's openssl extension to use "ldap over ssl" connections. The openssl extension ships as a dll with xampp. You must "tell" php to load this dll, e.g. by having an extension=nameofmodule.dll
in your php.ini
Run
echo 'ini: ', get_cfg_var('cfg_file_path');
It should show you which ini file your php installation uses (may differ between the php-apache-module and the php-cli version).
Open this file in an editor and search for
;extension=php_openssl.dll
remove the semicolon, save the file and re-start the apache.