Add bug number.

diff --cc lisp/ChangeLog
index 9e08889ba616794758033dc8f38329dec3531c22,81a5e1c9f533be9f676b7be8fdb06cab76c737c2..741f4ff48282396a809d50a1dac4ac723648302b
--- 1/lisp/ChangeLog
--- 2/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@@ -6,7 -96,7 +96,7 @@@
  2010-01-15  Kenichi Handa  <handa@m17n.org>
  
        * international/mule-cmds.el (canonicalize-coding-system-name):
--      Convert "msXXX", "ibmXXX", "windows-XXX" to "cpXXX".
++      Convert "msXXX", "ibmXXX", "windows-XXX" to "cpXXX" (Bug#5387).
  
  2010-01-15  Glenn Morris  <rgm@gnu.org>