gdb: PR 33384 invalid disassembler option message

This is the gdb part of fixing PR33384, where it is noted that an
error in a disassembler option prints the rest of the comma separated
option string rather than just the option in error.

Removing FOR_EACH_DISASSEMBLER_OPTION seemed a good idea to me, as we
then expose the strchr there which is useful in zero terminating the
option, and in the case of arm-tdep.c, to replace strcspn.  Also, if
the option is zero terminated we don't need disassembler_options_cmp.

Alternatively, you could do similarly to arm-tdep.c in disasm.c by
changing the error message to use %.*s with a length found by strcspn.
I rejected that smaller patch on the grounds that it makes for churn
in message translation.  I also prefer to see code using the standard
string functions.

Regression tested on x86_64-linux.  Message behaviour tested on
powerpc64le-linux and arm-linux-eabi.

	* arm-tdep.c (show_disassembly_style_sfunc): Don't use
	FOR_EACH_DISASSEMBLER_OPTION.  Use strchr needed for loop
	control to size option len.
	* disasm.c (set_disassembler_options): Don't use
	FOR_EACH_DISASSEMBLER_OPTION.  Overwrite comma in options with
	a zero.  Replace disassembler_options_cmp with strcmp.

gdb/arm-tdep.c

@@ -9641,13 +9641,20 @@ show_disassembly_style_sfunc (struct ui_file *file, int from_tty,
   const char *options = get_disassembler_options (gdbarch);
   const char *style = "";
   int len = 0;
-  const char *opt;
+  const char *opt = options;
 
-  FOR_EACH_DISASSEMBLER_OPTION (opt, options)
+  if (opt)
+    while (1)
+      {
+	const char *opt_end = strchr (opt, ',');
 	if (startswith (opt, "reg-names-"))
 	  {
 	    style = &opt[strlen ("reg-names-")];
-	len = strcspn (style, ",");
+	    len = opt_end ? opt_end - style : 99;
+	  }
+	if (!opt_end)
+	  break;
+	opt = opt_end + 1;
       }
 
   gdb_printf (file, "The disassembly style is \"%.*s\".\n", len, style);

gdb/disasm.c

@@ -1269,7 +1269,6 @@ set_disassembler_options (const char *prospective_options)
     = make_unique_xstrdup (prospective_options);
   char *options = remove_whitespace_and_extra_commas
     (prospective_options_local.get ());
-  const char *opt;
 
   /* Allow all architectures, even ones that do not support 'set disassembler',
      to reset their disassembler options to NULL.  */
@@ -1291,9 +1290,13 @@ set_disassembler_options (const char *prospective_options)
   valid_options = &valid_options_and_args->options;
 
   /* Verify we have valid disassembler options.  */
-  FOR_EACH_DISASSEMBLER_OPTION (opt, options)
+  char *opt = options;
+  while (1)
     {
       size_t i;
+      char *opt_end = strchr (opt, ',');
+      if (opt_end)
+	*opt_end = 0;
       for (i = 0; valid_options->name[i] != NULL; i++)
 	if (valid_options->arg != NULL && valid_options->arg[i] != NULL)
 	  {
@@ -1308,8 +1311,7 @@ set_disassembler_options (const char *prospective_options)
 	    if (valid_options->arg[i]->values == NULL)
 	      break;
 	    for (j = 0; valid_options->arg[i]->values[j] != NULL; j++)
-	      if (disassembler_options_cmp
+	      if (strcmp (arg, valid_options->arg[i]->values[j]) == 0)
-		    (arg, valid_options->arg[i]->values[j]) == 0)
 		{
 		  found = true;
 		  break;
@@ -1317,7 +1319,7 @@ set_disassembler_options (const char *prospective_options)
 	    if (found)
 	      break;
 	  }
-	else if (disassembler_options_cmp (opt, valid_options->name[i]) == 0)
+	else if (strcmp (opt, valid_options->name[i]) == 0)
 	  break;
       if (valid_options->name[i] == NULL)
 	{
@@ -1326,6 +1328,10 @@ set_disassembler_options (const char *prospective_options)
 		      opt);
 	  return;
 	}
+      if (!opt_end)
+	break;
+      *opt_end = ',';
+      opt = opt_end + 1;
     }
 
   *disassembler_options = options;