diff --git a/util/ack/ack.h b/util/ack/ack.h
index ede0df5a..0877a8c0 100644
--- a/util/ack/ack.h
+++ b/util/ack/ack.h
@@ -64,18 +64,6 @@ typedef struct {
 /* Return values of setpath() */
 enum f_path { F_OK, F_NOMATCH, F_NOPATH } ;
 
-/* Library routines */
-
-extern char *strchr();
-extern char *strrchr();
-extern char *strcpy();
-extern char *strcat();
-extern int  getpid();
-extern int  unlink();
-extern int  close();
-extern int  open();
-extern int  creat();
-
 /* Own routines */
 enum f_path getpath();
 enum f_path scan_end();
diff --git a/util/ack/main.c b/util/ack/main.c
index 009ad558..82c18888 100644
--- a/util/ack/main.c
+++ b/util/ack/main.c
@@ -6,6 +6,7 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include "ack.h"
 #include "list.h"
 #include "trans.h"
diff --git a/util/ack/run.c b/util/ack/run.c
index bbc3820d..8d0481a5 100644
--- a/util/ack/run.c
+++ b/util/ack/run.c
@@ -5,6 +5,7 @@
  */
 
 #include <stdlib.h>
+#include <string.h>
 #include "ack.h"
 #include "list.h"
 #include "trans.h"
diff --git a/util/opt/lookup.c b/util/opt/lookup.c
index dbe3f426..8cda8e51 100644
--- a/util/opt/lookup.c
+++ b/util/opt/lookup.c
@@ -18,8 +18,6 @@ static char rcsid[] = "$Id$";
  * Author: Hans van Staveren
  */
 
-extern char *strncpy();
-
 unsigned hash(string) char *string; {
 	register char *p;
 	register unsigned i,sum;