diff -Naur gperf-3.0.1.old/src/positions.h gperf-3.0.1/src/positions.h
--- gperf-3.0.1.old/src/positions.h	2003-04-07 17:48:19.000000000 +0800
+++ gperf-3.0.1/src/positions.h	2005-06-12 08:17:14.000000000 +0800
@@ -28,6 +28,9 @@
 
 /* This class denotes a set of byte positions, used to access a keyword.  */
 
+class PositionIterator;
+class PositionReverseIterator;
+
 class Positions
 {
   friend class PositionIterator;