*/
#include <stdlib.h>
+#include <string.h>
#include "puzzles.h"
/*
* dupstr is like strdup, but with the never-return-NULL property
* of smalloc (and also reliably defined in all environments :-)
*/
-char *dupstr(char *s) {
+char *dupstr(const char *s) {
char *r = smalloc(1+strlen(s));
strcpy(r,s);
return r;