Tried to make getopt() and friends more sus4-like in error handling

[Gregory Pietsch <gpietsch at comcast dot net>]

I finally got the a-ha for this. Okay to add? -- Gregory Pietsch

--- getopt.c.old    2012-08-26 19:24:27.466130300 -0400
+++ getopt.c    2012-08-26 19:54:39.118121500 -0400
@@ -71,6 +71,14 @@
 value of ordering.  In the case of RETURN_IN_ORDER, only `--' can cause
 getopt() and friends to return EOF with optind != argc.

+2012-08-26: Tried to make the error handling more sus4-like. The functions
+return a colon if getopt() and friends detect a missing argument and the
+first character of shortopts/optstring starts with a colon (`:'). If 
getopt()
+and friends detect a missing argument and shortopts/optstring does not 
start
+with a colon, the function returns a question mark (`?'). If it was a 
missing
+argument to a short option, optopt is set to the character in question. The
+colon goes in front of the ordering character (`+' or `-').
+
 COPYRIGHT NOTICE AND DISCLAIMER:

 Copyright (C) 1997 Gregory Pietsch
@@ -185,6 +193,7 @@
   int has_arg = -1;
   char *cp = 0;
   int arg_next = 0;
+  int initial_colon = 0;

   /* first, deal with silly parameters and easy stuff */
   if (argc == 0 || argv == 0 || (shortopts == 0 && longopts == 0)
@@ -200,6 +209,13 @@
   if (data->optind == 0)
     data->optind = data->optwhere = 1;

+  /* check for initial colon in shortopts */
+  if (*shortopts == ':')
+    {
+      ++shortopts;
+      initial_colon = 1;
+    }
+
   /* define ordering */
   if (shortopts != 0 && (*shortopts == '-' || *shortopts == '+'))
     {
@@ -359,12 +375,18 @@
         {
           fprintf (stderr, "%s: argument required for option `", argv[0]);
           if (longopt_match >= 0)
+        {
         fprintf (stderr, "--%s'\n", longopts[longopt_match].name);
+          data->optopt = initial_colon ? ':' : '\?';
+        }
           else
+        {
         fprintf (stderr, "-%c'\n", *cp);
+          data->optopt = *cp;
+        }
         }
       data->optind++;
-      return (data->optopt = ':');
+      return initial_colon ? ':' : '\?';
     }
       else
     {