diff --git a/src/include/utils/dynahash.h b/src/include/utils/dynahash.h
new file mode 100644
index 0000000000..ab78919c16
--- /dev/null
+++ b/src/include/utils/dynahash.h
@@ -0,0 +1,19 @@
+/*-------------------------------------------------------------------------
+ *
+ * dynahash--
+ *    POSTGRES dynahash.h file definitions
+ *
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: dynahash.h,v 1.1 1996/11/09 05:48:28 momjian Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef	DYNAHASH_H
+#define DYNAHASH_H
+
+extern int my_log2(long num);
+
+#endif DYNAHASH_H /* DYNAHASH_H */
+