"tr -d string1 string2" POSIXLY_CORRECT simplification

[Paul Eggert]

The coreutils tr source code has an unnecessary special case for
POSIXLY_CORRECT.  The SYNOPSIS section for tr
<http://www.opengroup.org/onlinepubs/000095399/utilities/tr.html> says
this:

    tr [-c | -C][-s] string1 string2
    tr -s [-c | -C] string1
    tr -d [-c | -C] string1
    tr -ds [-c | -C] string1 string2

None of these alternatives allow "tr -d string1 string2",
so tr is allowed to report an error in that case.

Here is a patch.

2004-06-05  Paul Eggert  <address@hidden>

        * src/tr.c (main): "tr -d a b" is now a fatal error even if
        POSIXLY_CORRECT is set.  The POSIX SYNOPSIS does not allow this
        option combination.

Index: src/tr.c
===================================================================
RCS file: /home/meyering/coreutils/cu/src/tr.c,v
retrieving revision 1.132
diff -p -u -r1.132 tr.c
--- src/tr.c    2 Jun 2004 08:50:24 -0000       1.132
+++ src/tr.c    5 Jun 2004 16:38:33 -0000
@@ -1739,19 +1739,11 @@ main (int argc, char **argv)
 deleting and squeezing repeats"));
 
   /* If --delete is given without --squeeze-repeats, then
-     only one string argument may be specified.  But POSIX
-     says to ignore any string2 in this case, so if POSIXLY_CORRECT
-     is set, pretend we never saw string2.  But I think
-     this deserves a fatal error, so that's the default.  */
+     only one string argument may be specified.  */
   if ((delete && !squeeze_repeats) && non_option_args != 1)
-    {
-      if (non_option_args == 2 && getenv ("POSIXLY_CORRECT"))
-       --non_option_args;
-      else
-       error (EXIT_FAILURE, 0,
-              _("only one string may be given when deleting \
+    error (EXIT_FAILURE, 0,
+          _("only one string may be given when deleting \
 without squeezing repeats"));
-    }
 
   if (squeeze_repeats && non_option_args == 0)
     error (EXIT_FAILURE, 0,