strip-rdoc.rb: binmode

* tool/strip-rdoc.rb: read in binary mode to get rid of errors by
  non-ascii characters.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44017 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/strip-rdoc.rb

@@ -1,5 +1,6 @@
 #!ruby
 
+ARGF.binmode
 source = ARGF.read
 source = source.gsub(%r{/\*([!*])((?!\*/).+?)\*/}m) do |comment|
   marker, comment = $1, $2