Use always POSIX API under Cygwin, even if _WIN32 was defined by previous includes.

Author: igaztanaga

include/boost/interprocess/detail/win32_api.hpp

@@ -31,10 +31,6 @@
 #include <string>
 #include <vector>
 
-#ifdef BOOST_USE_WINDOWS_H
-#include <windows.h>
-#endif
-
 #if defined(_MSC_VER)
 #  pragma once
 #  pragma comment( lib, "Advapi32.lib" )
@@ -43,6 +39,9 @@
 #endif
 
 #if defined (BOOST_INTERPROCESS_WINDOWS)
+#  ifdef BOOST_USE_WINDOWS_H
+#     include <windows.h>
+#  endif
 #  include <cstdarg>
 #  include <boost/detail/interlocked.hpp>
 #else

include/boost/interprocess/detail/workaround.hpp

@@ -25,7 +25,7 @@
 
 //#define BOOST_INTERPROCESS_FORCE_NATIVE_EMULATION
 
-#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)
+#if !defined(__CYGWIN__) && (defined(_WIN32) || defined(__WIN32__) || defined(WIN32))
    #define BOOST_INTERPROCESS_WINDOWS
    #if !defined(BOOST_INTERPROCESS_FORCE_NATIVE_EMULATION) && !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION)
       #define BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION