--- wdiff-0.5/wdiff.c	Sun Nov  6 02:57:23 1994
+++ wdiff-0.5-p/wdiff.c	Mon Oct 25 16:33:10 2004
@@ -109,6 +109,7 @@
 {
   {"copyright"   , 0, NULL, 'C'},
   {"version"     , 0, NULL, 'V'},
+  {"whitespace"  , 1, NULL, 'S'},
   {"no-deleted"  , 0, NULL, '1'},
   {"no-inserted" , 0, NULL, '2'},
   {"no-common"   , 0, NULL, '3'},
@@ -142,6 +143,7 @@
 const char *user_delete_end;	/* user specified string for end of delete */
 const char *user_insert_start;	/* user specified string for start of insert */
 const char *user_insert_end;	/* user specified string for end of insert */
+const char *user_space;	        /* user specified list of whitespace */
 
 int find_termcap;		/* initialize the termcap strings */
 const char *term_delete_start;	/* termcap string for start of delete */
@@ -382,6 +384,24 @@
   copy_mode = COPY_NORMAL;
 }
 
+/*---------------------------------------------------------.
+| Determine if a char is whitespace by user's definition.  |
+`---------------------------------------------------------*/
+static int
+iswhitespace (int c)
+{
+  if (user_space) {
+    char *u;
+    for (u = user_space; *u; u++) {
+      if (c == *u) return 1;
+    }
+    //return isspace (c);
+    return 0;
+  } else {
+    return isspace (c);
+  }
+}
+
 /*--------------------------------.
 | Skip over white space on SIDE.  |
 `--------------------------------*/
@@ -392,7 +412,7 @@
   if (interrupted)
     longjmp (signal_label, 1);
 
-  while (isspace (side->character))
+  while (iswhitespace (side->character))
     side->character = getc (side->file);
 }
 
@@ -406,7 +426,7 @@
   if (interrupted)
     longjmp (signal_label, 1);
 
-  while (side->character != EOF && !isspace (side->character))
+  while (side->character != EOF && !iswhitespace (side->character))
     side->character = getc (side->file);
   side->position++;
 }
@@ -421,7 +441,7 @@
   if (interrupted)
     longjmp (signal_label, 1);
 
-  while (isspace (side->character))
+  while (iswhitespace (side->character))
     {
 
       /* While changing lines, ensure we stop any special display prior
@@ -507,7 +527,7 @@
   if (interrupted)
     longjmp (signal_label, 1);
 
-  while (side->character != EOF && !isspace (side->character))
+  while (side->character != EOF && !iswhitespace (side->character))
     {
 
       /* In printer mode, act according to copy_mode.  If copy_mode is not
@@ -1139,6 +1159,8 @@
 main (int argc, char *const argv[])
 {
   int option_char;		/* option character */
+  char *c, *u;
+  char s;
 
   /* Decode arguments.  */
 
@@ -1173,7 +1195,7 @@
   count_changed_left = 0;
   count_changed_right = 0;
 
-  while (option_char = getopt_long (argc, argv, "123CVahidlnpstw:x:y:z:",
+  while (option_char = getopt_long (argc, argv, "123CVS:ahidlnpstw:x:y:z:",
 				    longopts, NULL),
 	 option_char != EOF)
     switch (option_char)
@@ -1197,6 +1219,43 @@
       case 'v':
 	printf ("GNU %s %s\n%s\n", PRODUCT, VERSION, copyright);
 	exit (0);
+
+      case 'S':
+	user_space = malloc (strlen (optarg));
+	u = user_space;
+	for (c = optarg; *c; c++) {
+	  if (*c == '\\') {
+	    switch (*(++c)) {
+	    case 'n':
+	      *u++ = '\n';
+	      break;
+	    case 't':
+	      *u++ = '\t';
+	      break;
+	    case 'v':
+	      *u++ = '\v';
+	      break;
+	    case 'r':
+	      *u++ = '\r';
+	      break;
+	    case '\\':
+	      *u++ = '\\';
+	      break;
+	    case 'S':
+	      //things in isspace
+	      for (s = 0; s < 127; s++) {
+		if (isspace (s)) {
+		  *u++ = s;
+		}
+	      }
+	      break;
+	    }
+	  } else {
+	    *u++ = *c;
+	  }
+	}
+	*u = 0;
+	break;
 
       case 'a':
 	autopager = 1;
diff -ru wdiff-0.5/wdiff.texi wdiff-0.5-p/wdiff.texi
--- wdiff-0.5/wdiff.texi	Tue Nov  1 12:36:52 1994
+++ wdiff-0.5-p/wdiff.texi	Mon Oct 25 16:38:01 2004
@@ -311,6 +311,15 @@
 distinguishing where such text ends; in this case the default end insert
 string is @address@hidden
 
address@hidden --whitespace @var{argument}
address@hidden -S @var{argument}
+
+Use @var{argument} as a list of characters to be considered
address@hidden  The default is to use your system's C library's
+isspace function.  @var{argument} is processed for escaped characters
+as in C strings.  The additional escape @code{\\S} is accepted and
+includes characters matched by isspace.
+
 @item --avoid-wraps
 @itemx -n
 Avoid spanning the end of line while showing deleted or inserted text.