preparation for 5.0rc2 windows and cygwin binary

[Tatsuro M. <tma...@ya...>]

Today I checked out the branch-5-0-stable source.
I confirmed it was able to be built on native windows (mingw) and the cygwin.
(Both 32 and 64 bit binaries were built.)

If the official 5.0rc2 source will be uploaded, 
I will be able to make binaries for windows and cygwin 
and upload those on my web.

Tatsuro