GoogleのWindowsへポーティングするためのヘッダファイル

http://google-perftools.googlecode.com/svn/trunk/src/windows/port.h

* These are some portability typedefs and defines to make it a bit
* easier to compile this code under VC++.
*
* Several of these are taken from glib:
* http://developer.gnome.org/doc/API/glib/glib-windows-compatability-functions.html