Ticket #21103: patch

(a) wp-includes/wp-db.php vs. (b) -

@@ -932 +932 @@
                 else
                         $error_str = sprintf( __( 'WordPress database error %1$s for query %2$s' ), $str, $this->last_query );
 
+                $log_file = @ini_get('error_log');
                 if ( function_exists( 'error_log' )
-                        && ( $log_file = @ini_get( 'error_log' ) )
-                        && ( 'syslog' == $log_file || @is_writable( $log_file ) )
+                        && ( '' == $log_file || 'syslog' == $log_file || @is_writable( $log_file ) )
                         )
                         @error_log( $error_str );