du: recognize -d N as equivalent to --max-depth=N

* NEWS (New features): Mention it.
* src/du.c (DEBUG_OPT): Remove.  Use long-named ---debug instead.
Commented out.
(MAX_DEPTH_OPTION): Remove.  Use 'd' instead.
(main): Insert literal "d:"; remove DEBUG_OPT.
* doc/coreutils.texi (du invocation): Add -d to indices.
* tests/du/max-depth: Exercise -d, too.

NEWS

@@ -4,6 +4,9 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 ** New features
 
+  du recognizes -d N as equivalent to --max-depth=N, for compatibility
+  with FreeBSD.
+
   sort now accepts the --debug option, to highlight the part of the
   line significant in the sort, and warn about questionable options.
 

doc/coreutils.texi

@@ -10427,7 +10427,9 @@ This option is equivalent to @option{--block-size=1M}.
 For each symbolic links encountered by @command{du},
 consider the disk space used by the symbolic link.
 
+@item -d @var{depth}
 @item --max-depth=@var{depth}
+@opindex -d @var{depth}
 @opindex --max-depth=@var{depth}
 @cindex limiting output of @command{du}
 Show the total for each directory (and file if --all) that is at

src/du.c

@@ -56,10 +56,8 @@ extern bool fts_debug;
 
 #if DU_DEBUG
 # define FTS_CROSS_CHECK(Fts) fts_cross_check (Fts)
-# define DEBUG_OPT "d"
 #else
 # define FTS_CROSS_CHECK(Fts)
-# define DEBUG_OPT
 #endif
 
 /* Initial size of the hash table.  */
@@ -192,7 +190,7 @@ enum
   EXCLUDE_OPTION,
   FILES0_FROM_OPTION,
   HUMAN_SI_OPTION,
-  MAX_DEPTH_OPTION,
+  FTS_DEBUG,
   TIME_OPTION,
   TIME_STYLE_OPTION
 };
@@ -204,6 +202,7 @@ static struct option const long_options[] =
   {"block-size", required_argument, NULL, 'B'},
   {"bytes", no_argument, NULL, 'b'},
   {"count-links", no_argument, NULL, 'l'},
+  /* {"-debug", no_argument, NULL, FTS_DEBUG}, */
   {"dereference", no_argument, NULL, 'L'},
   {"dereference-args", no_argument, NULL, 'D'},
   {"exclude", required_argument, NULL, EXCLUDE_OPTION},
@@ -211,7 +210,7 @@ static struct option const long_options[] =
   {"files0-from", required_argument, NULL, FILES0_FROM_OPTION},
   {"human-readable", no_argument, NULL, 'h'},
   {"si", no_argument, NULL, HUMAN_SI_OPTION},
-  {"max-depth", required_argument, NULL, MAX_DEPTH_OPTION},
+  {"max-depth", required_argument, NULL, 'd'},
   {"null", no_argument, NULL, '0'},
   {"no-dereference", no_argument, NULL, 'P'},
   {"one-file-system", no_argument, NULL, 'x'},
@@ -312,7 +311,7 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   -x, --one-file-system    skip directories on different file systems\n\
   -X, --exclude-from=FILE  exclude files that match any pattern in FILE\n\
       --exclude=PATTERN    exclude files that match PATTERN\n\
-      --max-depth=N     print the total for a directory (or file, with --all)\n\
+  -d, --max-depth=N     print the total for a directory (or file, with --all)\n\
                           only if it is N or fewer levels below the command\n\
                           line argument;  --max-depth=0 is the same as\n\
                           --summarize\n\
@@ -694,7 +693,7 @@ main (int argc, char **argv)
   for (;;)
     {
       int oi = -1;
-      int c = getopt_long (argc, argv, DEBUG_OPT "0abchHklmsxB:DLPSX:",
+      int c = getopt_long (argc, argv, "0abd:chHklmsxB:DLPSX:",
                            long_options, &oi);
       if (c == -1)
         break;
@@ -702,7 +701,7 @@ main (int argc, char **argv)
       switch (c)
         {
 #if DU_DEBUG
-        case 'd':
+        case FTS_DEBUG:
           fts_debug = true;
           break;
 #endif
@@ -744,7 +743,7 @@ main (int argc, char **argv)
           output_block_size = 1024;
           break;
 
-        case MAX_DEPTH_OPTION:		/* --max-depth=N */
+        case 'd':		/* --max-depth=N */
           {
             unsigned long int tmp_ulong;
             if (xstrtoul (optarg, NULL, 0, &tmp_ulong, NULL) == LONGINT_OK

tests/du/max-depth

@@ -28,4 +28,11 @@ cut -f2- out > k && mv k out
 compare out exp || fail=1
 compare err /dev/null || fail=1
 
+# Repeat, but use -d 1.
+printf 'a/b\na\n' > exp || framework_failure_
+du -d 1 a > out 2>err || fail=1
+cut -f2- out > k && mv k out
+compare out exp || fail=1
+compare err /dev/null || fail=1
+
 Exit $fail