describe: when failing, tell the user about options that work

diff --git a/diff.h b/diff.h
index 23cd90c2e64cf8be44999be812a0765cbe36c9f8..6616877ee5d15a8101cbdea0271cc18f8837d2f1 100644 (file)
--- a/diff.h
+++ b/diff.h
@@ -69,6 +69,9 @@ typedef void (*diff_format_fn_t)(struct diff_queue_struct *q,
 #define DIFF_OPT_TST(opts, flag)    ((opts)->flags & DIFF_OPT_##flag)
 #define DIFF_OPT_SET(opts, flag)    ((opts)->flags |= DIFF_OPT_##flag)
 #define DIFF_OPT_CLR(opts, flag)    ((opts)->flags &= ~DIFF_OPT_##flag)
+#define DIFF_XDL_TST(opts, flag)    ((opts)->xdl_opts & XDF_##flag)
+#define DIFF_XDL_SET(opts, flag)    ((opts)->xdl_opts |= XDF_##flag)
+#define DIFF_XDL_CLR(opts, flag)    ((opts)->xdl_opts &= ~XDF_##flag)
 
 struct diff_options {
        const char *filter;
@@ -265,4 +268,6 @@ extern int diff_result_code(struct diff_options *, int);
 
 extern void diff_no_index(struct rev_info *, int, const char **, int, const char *);
 
+extern int index_differs_from(const char *def, int diff_flags);
+
 #endif /* DIFF_H */