For strchr() / memset().

Index: simpleclient/tkphone/tones.c
--- simpleclient/tkphone/tones.c.orig
+++ simpleclient/tkphone/tones.c
@@ -33,6 +33,7 @@
 #  include <stdio.h>
 #endif
 #include <strings.h>
+#include <string.h>
 #include <stdlib.h>
 #include <math.h>
 #include "tones.h"