Visual Studio compilers have different header files.
I looked through the files that qpid cpp uses for including Visual Studio header files.
It looks like most of the diffences in header files are set up in Boost.
Boost uses the macro BOOST_WINDOWS.
Maybe we could use PROTON_WINDOWS for including the windows header files.
If you don't want a new macro, we can use one of the Visual Studio specific macro (_WINDOWS)
for the header files.
It's not really a CPLUSPLUS vs. C issue, since many of the header files are specific to Windows.
(for example winsock2.h which is used by C++ and C in Visual Studio).
Also, some of the current header files are not used on Windows, but may be used by CYGWIN or MinGW.
If this sounds okay, I'll set up a patch for including the necessary windows header files.