[MSVC] Fix link error in debug configuration

[fredroy]

"Hack" to force to link with the release version of python3x.lib
The link command is contained deep in python (pyconfig.h):

/* For an MSVC DLL, we can nominate the .lib files used by extensions */
#ifdef MS_COREDLL
#       if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
                /* not building the core - must be an ext */
#               if defined(_MSC_VER)
                        /* So MSVC users need not specify the .lib
                        file in their Makefile (other compilers are
                        generally taken care of by distutils.) */
#                       if defined(_DEBUG)
#                               pragma comment(lib,"python39_d.lib")
#                       elif defined(Py_LIMITED_API)
#                               pragma comment(lib,"python3.lib")
#                       else
#                               pragma comment(lib,"python39.lib")
#                       endif /* _DEBUG */
#               endif /* _MSC_VER */
#       endif /* Py_BUILD_CORE */
#endif /* MS_COREDLL */

So according to various sources, the "best" way is to disable debug before including python.h
https://bugs.python.org/issue22411

[hugtalbot]

@epernod and @Camille-K do not hesitate to let us know if you tested it !