MDL-51784 general: Adding missing php4 style constructors

Adding them to maintain backwards compatibility.

mod/wiki/diff/difflib.php

@@ -319,7 +319,14 @@ class ouwiki_line {
             }
         }
     }
-    
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     */
+    public function ouwiki_line($data, $linepos) {
+        self::__construct($data, $linepos);
+    }
+
     /**
      * @return string Normalised string representation of this line object
      */
@@ -372,6 +379,13 @@ class ouwiki_word {
         $this->word=$word;
         $this->start=$start;
     }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     */
+    public function ouwiki_word($word, $start) {
+        self::__construct($word, $start);
+    }
 }
 
 /**
@@ -511,6 +525,13 @@ class ouwiki_changes {
         }
     }
 
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     */
+    public function ouwiki_changes($diff, $count2) {
+        self::__construct($diff, $count2);
+    }
+
     /**
      * Find deleted lines. These are lines in file1 that
      * cannot be present even in modified form in file2