extern int git_diff_basic_config(const char *var, const char *value, void *cb);
extern int git_diff_ui_config(const char *var, const char *value, void *cb);
extern int diff_use_color_default;
extern int git_diff_basic_config(const char *var, const char *value, void *cb);
extern int git_diff_ui_config(const char *var, const char *value, void *cb);
extern int diff_use_color_default;