#84173 by plumbley and Jax. Don't assume the database port is set.

install.php

@@ -110,7 +110,7 @@ function install_verify_settings() {
     $db_user = urldecode($url['user']);
     $db_pass = urldecode($url['pass']);
     $db_host = urldecode($url['host']);
-    $db_port = urldecode($url['port']);
+    $db_port = isset($url['port']) ? urldecode($url['port']) : '';
     $db_path = ltrim(urldecode($url['path']), '/');
     $settings_file = './'. conf_path() .'/settings.php';
 
@@ -132,7 +132,7 @@ function install_change_settings($profile = 'default', $install_locale = '') {
   $db_user = urldecode($url['user']);
   $db_pass = urldecode($url['pass']);
   $db_host = urldecode($url['host']);
-  $db_port = urldecode($url['port']);
+  $db_port = isset($url['port']) ? urldecode($url['port']) : '';
   $db_path = ltrim(urldecode($url['path']), '/');
   $settings_file = './'. conf_path() .'/settings.php';