ZooKeeper C Client for Windows: should include winports.h

When building the C client on Windows with CMake:

cmake -DWANT_SYNCAPI=OFF -DCMAKE_GENERATOR_PLATFORM=x64

With this input, the header file winports.h will not be added in these files:

zk_log.c

zk_adaptor.h

Also, I think winports.h should be added to zookeeper.c

Without winports.h compiling will fail on Windows. Errors are about strtok_r and localtime_r - the Windows mappings in winports.h are missing. 

I am guessing that other important includes are missing too (like Windows Sockets).

One solution could be to extract the winports.h include out from the THREADED preprocessor, to a separate one:

#ifdef WIN32

#include "winport.h"

#endif