Native win32 build instructions using Microsoft Visual Studio 2015 (MSVC).

Requirements:
 * zlib is installed automatically from NuGet,
   but probably requires the NuGet VS extension.
 * OpenSSL-win32 must be installed in C:\OpenSSL-win32 and C:\OpenSSL-Win64
   depending on your architecture.
   Download and install the latest v1.0.2 non-light package from:
   https://slproweb.com/products/Win32OpenSSL.html
   (This would be using NuGet too but the current
    OpenSSL packages are outdated and with broken
    dependencies, so no luck)

The Visual Studio solution file for librdkafka resides in win32/librdkafka.sln

Artifacts:
 - C library
 - C++ library
 - rdkafka_example, rdkafka_performance
 - tests


If you build librdkafka with an external tool (ie CMake) you can get rid of the 
__declspec(dllexport) / __declspec(dllimport) decorations by adding a define
-DLIBRDKAFKA_STATICLIB to your CFLAGS