fix to multiple alias expansion problem in command substitutions

lib/sh/shquote.c

@@ -313,46 +313,49 @@ sh_backslash_quote (string, table, flags)
 
 #if defined (PROMPT_STRING_DECODE) || defined (TRANSLATABLE_STRINGS)
 /* Quote characters that get special treatment when in double quotes in STRING
-   using backslashes.  Return a new string. */
+   using backslashes. If FLAGS == 1, also make `unsafe' characters visible by
+   translating them to a standard ^X/M-X representation (not yet implemented).
+   Return a new string. */
 char *
 sh_backslash_quote_for_double_quotes (string, flags)
      char *string;
      int flags;
 {
   unsigned char c;
-  char *result, *r, *s, *send;
-  size_t slen;
+  char *result, *send;
+  size_t slen, sind, rind;
   int mb_cur_max;
   DECLARE_MBSTATE;
  
   slen = strlen (string);
   send = string + slen;
   mb_cur_max = MB_CUR_MAX;
-  result = (char *)xmalloc (2 * slen + 1);
+  result = (char *)xmalloc ((flags == 1 ? 3 : 2) * slen + 1);
 
-  for (r = result, s = string; s && (c = *s); s++)
+  for (rind = sind = 0; c = string[sind]; sind++)
     {
       /* Backslash-newline disappears within double quotes, so don't add one. */
+
       if ((sh_syntaxtab[c] & CBSDQUOTE) && c != '\n')
-	*r++ = '\\';
+	result[rind++] = '\\';
       /* I should probably use the CSPECL flag for these in sh_syntaxtab[] */
       else if (c == CTLESC || c == CTLNUL)
-	*r++ = CTLESC;		/* could be '\\'? */
+	result[rind++] = CTLESC;		/* could be '\\'? */
 
 #if defined (HANDLE_MULTIBYTE)
       if ((locale_utf8locale && (c & 0x80)) ||
 	  (locale_utf8locale == 0 && mb_cur_max > 1 && is_basic (c) == 0))
 	{
-	  COPY_CHAR_P (r, s, send);
-	  s--;		/* compensate for auto-increment in loop above */
+	  COPY_CHAR_I (result, rind, string, send, sind);
+	  sind--;	/* compensate for auto-increment in loop above */
 	  continue;
 	}
 #endif
 
-      *r++ = c;
+      result[rind++] = c;
     }
 
-  *r = '\0';
+  result[rind] = '\0';
   return (result);
 }
 #endif /* PROMPT_STRING_DECODE */