cycle-check.h fix imported from coreutils

[Paul Eggert]

I installed this into gnulib:

2006-07-03  Jim Meyering  <address@hidden>

        * cycle-check.h (CYCLE_CHECK_REFLECT_CHDIR_UP): Abort if this
        macro is used before the first cycle_check call.

--- lib/cycle-check.h   3 Jul 2006 08:32:46 -0000       1.3
+++ lib/cycle-check.h   4 Jul 2006 05:58:07 -0000
@@ -45,6 +45,9 @@ bool cycle_check (struct cycle_check_sta
 # define CYCLE_CHECK_REFLECT_CHDIR_UP(State, SB_dir, SB_subdir)        \
   do                                                           \
     {                                                          \
+      /* You must call cycle_check at least once before using this macro.  */ \
+      if ((State)->chdir_counter == 0)                         \
+        abort ();                                              \
       if (SAME_INODE ((State)->dev_ino, SB_subdir))            \
        {                                                       \
          (State)->dev_ino.st_dev = (SB_dir).st_dev;            \