#define DIFF_SETUP_USE_CACHE 2
#define DIFF_SETUP_USE_SIZE_CACHE 4
+extern int git_diff_config(const char *var, const char *value);
extern void diff_setup(struct diff_options *);
extern int diff_opt_parse(struct diff_options *, const char **, int);
extern int diff_setup_done(struct diff_options *);