In `WP_Tax_Query`, declare `$primary_table` and `$primary_id_column` as properties.

See #30224.


git-svn-id: https://develop.svn.wordpress.org/trunk@30184 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/taxonomy.php

@@ -681,6 +681,24 @@ class WP_Tax_Query {
 	 */
 	public $queried_terms = array();
 
+	/**
+	 * Database table that where the metadata's objects are stored (eg $wpdb->users).
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 * @var string
+	 */
+	public $primary_table;
+
+	/**
+	 * Column in primary_table that represents the ID of the object.
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 * @var string
+	 */
+	public $primary_id_column;
+
 	/**
 	 * Constructor.
 	 *