win32 patch

I have applied the following patch. It was submitted a while ago.:

For application to HEAD, following community review.

* Changes incorrect CYGWIN defines to __CYGWIN__

* Some localtime returns NULL checks (when unchecked cause SEGVs under
Win32
regression tests)

* Rationalized CreateSharedMemoryAndSemaphores and
AttachSharedMemoryAndSemaphores (Bruce, I finally remembered to do it);
requires attention.

Claudio Natoli

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