Use Python3 if compatible
Add support for Python3 in CMake for updated Python module (see !35).
Checks for required unistd.h header and F_GETFL symbol in fcntl.h (not available on MSVC) similar to libxml2.
Add support for Python3 in CMake for updated Python module (see !35).
Checks for required unistd.h header and F_GETFL symbol in fcntl.h (not available on MSVC) similar to libxml2.