extern void setup_work_tree(void);
extern const char *setup_git_directory_gently(int *);
extern const char *setup_git_directory(void);
-extern const char *prefix_path(const char *prefix, int len, const char *path);
+extern char *prefix_path(const char *prefix, int len, const char *path);
extern const char *prefix_filename(const char *prefix, int len, const char *path);
extern int check_filename(const char *prefix, const char *name);
extern void verify_filename(const char *prefix, const char *name);