bignum.c: suppress warning

* bignum.c (rb_big_mul_karatsuba): suppress logical-op-parentheses
  warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42470 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
re.c: suppress warning

* re.c (rb_memsearch): suppress parentheses warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42471 b2dd03c8-39d4-4d8f-98ff-823fe69b080e