Bug #1671: $-W is assignable
http://redmine.ruby-lang.org/issues/show/1671
e$B5/I<<Te(B: Yuki S.
e$B%9%F!<%?%9e(B: Open, e$BM%@hEYe(B: Normal
e$BC4Ev<Te(B: Yusuke E., e$B%+%F%4%je(B: core, Target version: 1.9.2
ruby -v: ruby 1.9.2dev (2009-06-21 trunk 23774) [i386-darwin9.7.0]
$-W = 2
$-W = :not_a_number
e$B%I%-%e%a%s%H$K$h$k$He(B$-We$B$Oe(Breadonlye$B$G$"$k$Y$-$G$9!#e(B