Log Message:
Update 6.39 to 6.41
6.41 Sat Sep  6 22:08:46 CEST 2014
        - restore portability to perl 5.8.x.
        - give new Coro's a valid GvHV(PL_hintgv) - this is slow and takes
          up some memory, but fixes "use feature" and similar modules
          when used inside a Coro.
        - allow zero as argument to Coro::Channel to mean the same thing
          as no argument. this works with older versions as well,
          but wasn't legal until now.
        - slightly better c header file detection.