Merge branch 'nd/log-show-linear-break'

Attempts to show where a single-strand-of-pearls break in "git log"
output.

* nd/log-show-linear-break:
  log: add --show-linear-break to help see non-linear history
  object.h: centralize object flag allocation

bisect.c

@@ -21,8 +21,7 @@ static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
 static const char *argv_update_ref[] = {"update-ref", "--no-deref", "BISECT_HEAD", NULL, NULL};
 
-/* bits #0-15 in revision.h */
-
+/* Remember to update object flag allocation in object.h */
 #define COUNTED		(1u<<16)
 
 /*