diff -up gsm-1.0-pl16/add-test/add_test.c.warn gsm-1.0-pl16/add-test/add_test.c
--- gsm-1.0-pl16/add-test/add_test.c.warn	2006-04-26 21:14:25.000000000 +0200
+++ gsm-1.0-pl16/add-test/add_test.c	2016-11-24 10:35:09.642537236 +0100
@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include "gsm.h"
 
@@ -29,7 +30,7 @@ word M_gsm_abs P((word op1));
 longword M_gsm_L_mult P((word op1, word op2));
 longword M_gsm_L_add P((longword op1, longword op2));
 
-help()
+void help(void)
 {
 puts( "  add a b      sub a b     mult a b   div    a b" );
 puts( "L_add A B    L_sub A B   L_mult A B   mult_r a b" );
diff -up gsm-1.0-pl16/src/toast.c.warn gsm-1.0-pl16/src/toast.c
--- gsm-1.0-pl16/src/toast.c.warn	2006-04-26 21:14:26.000000000 +0200
+++ gsm-1.0-pl16/src/toast.c	2016-11-24 10:35:15.266571608 +0100
@@ -6,6 +6,8 @@
 
 /* $Header: /tmp_amd/presto/export/kbs/jutta/src/gsm/RCS/toast.c,v 1.8 1996/07/02 10:41:04 jutta Exp $ */
 
+#include	<stdio.h>
+#include	<getopt.h>
 #include	"toast.h"
 
 /*  toast -- lossy sound compression using the gsm library.