make cn or uid configurable

etc/authentication.php

@@ -3,8 +3,9 @@ $realm = "MY REALM HERE";
 $ldaphost = "my.ldap.host";
 $ldaptls = "yes";
 $ldapbase = "dc=my,dc=server,dc=com";
+$checkuser = "cn";
 function basicAuth() {
-    header('WWW-Authenticate: Basic realm="'.$REALM.'"');
+    header('WWW-Authenticate: Basic realm="'.$realm.'"');
     header('HTTP/1.0 401 Unauthorized');
     exit;
 }
@@ -20,7 +21,7 @@ if (!isset($_SERVER['PHP_AUTH_USER'])) {
     if ($ldaptls!="no" && $ldaptls!=0 && $ldaptlS)
         ldap_start_tls($ldapconn)
             or error_die($ldapconn, "cannot start LDAP TLS");
-    $ldapbind = @ldap_bind($ldapconn, 'uid='.$tstusername.','.$ldapbase, $password)
+    $ldapbind = @ldap_bind($ldapconn, $checkuser.'='.$tstusername.','.$ldapbase, $password)
         or basicAuth();
     $username = $tstuserbname;
 }