void fn_init (void);
-char *fn_interp_vars (const char *input, const char *(*getenv) (const char *));
+struct string;
+void fn_interp_vars (struct string *target,
+ const char *(*getenv) (const char *));
char *fn_tilde_expand (const char *fn);
char *fn_search_path (const char *basename, const char *path,
const char *prepend);