gdb_rl_find_completion_word: Remove 'found_quote' local

Compiling GDB with current git Clang (future 13) runs into this:

 src/gdb/completer.c:287:18: error: variable 'found_quote' set but not used [-Werror,-Wunused-but-set-variable]
   int scan, end, found_quote, delimiter, pass_next, isbrk;
		  ^

gdb_rl_find_completion_word came to life as a modified (stripped down)
version of readline's internal _rl_find_completion_word function.
When I added it, I don't remember whether I realized that
'found_quote' wasn't really necessary.  Maybe I kept it thinking of
keeping the source code in sync with readline?  I don't recall
anymore.  Since the function is already stripped down compared to the
original, stripping it down some more doesn't hurt.

So fix the issue by removing the unnecessary code.

gdb/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	* completer.c (RL_QF_SINGLE_QUOTE, RL_QF_DOUBLE_QUOTE)
	(RL_QF_BACKSLASH, RL_QF_OTHER_QUOTE): Delete.
	(gdb_rl_find_completion_word): Remove write-only 'found_quote'
	local.

gdb/ChangeLog

@@ -1,3 +1,10 @@
+2021-06-07  Pedro Alves  <pedro@palves.net>
+
+	* completer.c (RL_QF_SINGLE_QUOTE, RL_QF_DOUBLE_QUOTE)
+	(RL_QF_BACKSLASH, RL_QF_OTHER_QUOTE): Delete.
+	(gdb_rl_find_completion_word): Remove write-only 'found_quote'
+	local.
+
 2021-06-07  Pedro Alves  <pedro@palves.net>
 
 	* nat/amd64-linux-siginfo.c (union nat_sigval): Rename to ...

gdb/completer.c

@@ -250,14 +250,6 @@ filename_completer_handle_brkchars (struct cmd_list_element *ignore,
     (gdb_completer_file_name_break_characters);
 }
 
-/* Possible values for the found_quote flags word used by the completion
-   functions.  It says what kind of (shell-like) quoting we found anywhere
-   in the line. */
-#define RL_QF_SINGLE_QUOTE      0x01
-#define RL_QF_DOUBLE_QUOTE      0x02
-#define RL_QF_BACKSLASH         0x04
-#define RL_QF_OTHER_QUOTE       0x08
-
 /* Find the bounds of the current word for completion purposes, and
    return a pointer to the end of the word.  This mimics (and is a
    modified version of) readline's _rl_find_completion_word internal
@@ -284,7 +276,7 @@ gdb_rl_find_completion_word (struct gdb_rl_completion_word_info *info,
 			     int *qc, int *dp,
 			     const char *line_buffer)
 {
-  int scan, end, found_quote, delimiter, pass_next, isbrk;
+  int scan, end, delimiter, pass_next, isbrk;
   char quote_char;
   const char *brkchars;
   int point = strlen (line_buffer);
@@ -301,7 +293,7 @@ gdb_rl_find_completion_word (struct gdb_rl_completion_word_info *info,
     }
 
   end = point;
-  found_quote = delimiter = 0;
+  delimiter = 0;
   quote_char = '\0';
 
   brkchars = info->word_break_characters;
@@ -311,8 +303,6 @@ gdb_rl_find_completion_word (struct gdb_rl_completion_word_info *info,
       /* We have a list of characters which can be used in pairs to
 	 quote substrings for the completer.  Try to find the start of
 	 an unclosed quoted substring.  */
-      /* FOUND_QUOTE is set so we know what kind of quotes we
-	 found.  */
       for (scan = pass_next = 0;
 	   scan < end;
 	   scan++)
@@ -330,7 +320,6 @@ gdb_rl_find_completion_word (struct gdb_rl_completion_word_info *info,
 	  if (quote_char != '\'' && line_buffer[scan] == '\\')
 	    {
 	      pass_next = 1;
-	      found_quote |= RL_QF_BACKSLASH;
 	      continue;
 	    }
 
@@ -351,13 +340,6 @@ gdb_rl_find_completion_word (struct gdb_rl_completion_word_info *info,
 	      /* Found start of a quoted substring.  */
 	      quote_char = line_buffer[scan];
 	      point = scan + 1;
-	      /* Shell-like quoting conventions.  */
-	      if (quote_char == '\'')
-		found_quote |= RL_QF_SINGLE_QUOTE;
-	      else if (quote_char == '"')
-		found_quote |= RL_QF_DOUBLE_QUOTE;
-	      else
-		found_quote |= RL_QF_OTHER_QUOTE;
 	    }
 	}
     }