--- lib/lex.c.orig	Sat Nov 29 13:47:57 1997
+++ lib/lex.c	Sat Nov 29 13:48:17 1997
@@ -125,6 +125,7 @@
 #include <math.h>
 #ifdef USE_READLINE
 #include <readline/readline.h>
+#include <readline/history.h>
 #endif /* USE_READLINE */
 #if STDC_HEADERS
 #include <stdlib.h>		/* for malloc */
