[Backport #2513](Closed) CC is ignored in ext

e$B%A%1%C%He(B #2513 e$B$,99?7$5$l$^$7$?!#e(B (by Shyouhei U.)

e$B%9%F!<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B

Applied in changeset r26173.

http://redmine.ruby-lang.org/issues/show/2513