void handle_ignore_submodules_arg(struct diff_options *diffopt, const char *);
void show_submodule_summary(FILE *f, const char *path,
unsigned char one[20], unsigned char two[20],
void handle_ignore_submodules_arg(struct diff_options *diffopt, const char *);
void show_submodule_summary(FILE *f, const char *path,
unsigned char one[20], unsigned char two[20],