extern int cmd_diff_index(int argc, const char **argv, char **envp);
extern int cmd_diff_stages(int argc, const char **argv, char **envp);
extern int cmd_diff_tree(int argc, const char **argv, char **envp);
extern int cmd_diff_index(int argc, const char **argv, char **envp);
extern int cmd_diff_stages(int argc, const char **argv, char **envp);
extern int cmd_diff_tree(int argc, const char **argv, char **envp);