* bignum.c (LSHIFTX): Defined to suppress a warning.
  (RSHIFTX): Ditto.
  (CLEAR_LOWBITS): Use LSHIFTX and RSHIFTX.
  (FILL_LOWBITS): Use LSHIFTX.
  Reported by ko1 via IRC.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41554 b2dd03c8-39d4-4d8f-98ff-823fe69b080e