multi3d compilation on windows?

Author: Teseo Schneider

setup.py

@@ -60,8 +60,7 @@ def build_extension(self, ext):
             cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'.format(cfg.upper(), extdir)]
             if sys.maxsize > 2**32:
                 cmake_args += ['-A', 'x64']
-            build_args += ['--', '/m']
-            build_args += ['--', '/MP']
+            build_args += ['--', '/m', '/MP']
         else:
             cmake_args += ['-DCMAKE_BUILD_TYPE=' + cfg]
             build_args += ['--', '-j2']