headers are inconsistent at this macro.  [ruby-core:01432]

* ext/curses/extconf.rb: check if _XOPEN_SOURCE_EXTENDED breaks.

* ext/tcltklib/stubs.c: Status macro in X11/Xthreads.h bothers
  winspool.h

* instruby.rb: make list at first instead of iterator.
  [ruby-talk:79347]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4405 b2dd03c8-39d4-4d8f-98ff-823fe69b080e