(detect_coding): Don't overflow coding->carryover.

src/ChangeLog

@@ -5,6 +5,7 @@
 2009-02-19  Kenichi Handa  <handa@m17n.org>
 	* coding.c (detect_coding): Preserve coding->mode.
+	Don't overflow coding->carryover.
 2009-02-18  Dan Nicolaescu  <dann@ics.uci.edu>

src/coding.c

@@ -6805,6 +6805,8 @@ decode_coding (coding)
 	     coding->carryover.  */
 	  unsigned char *p = coding->carryover;
 
+	  if (nbytes > sizeof coding->carryover)
+	    nbytes = sizeof coding->carryover;
 	  coding->carryover_bytes = nbytes;
 	  while (nbytes-- > 0)
 	    *p++ = *src++;