[ruby-core:7600]
* ext/tk/tcltklib.c: fix SEGV at exit. [ruby-talk:186489]
* ext/tk/tkutil/tkutil.c: follow to changing specification of
  instance_eval on ruby-1.9.x.
* ext/tk/lib/tk.rb: ditto.
* ext/tk/lib/multi-tk.rb: ditto.
* ext/tk/lib/tk.rb: remove warning about redefinition of methods.
* ext/tk/lib/tk/variable.rb: remove warning about unseting Tcl
 variables.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@10078 b2dd03c8-39d4-4d8f-98ff-823fe69b080e