Don't use hacks, just cythonize.

--- a/setup.py
+++ b/setup.py
@@ -22,9 +22,7 @@ except ImportError:
 
 import os, sys
 
-if '--cythonize' in sys.argv:
-    # Remove the special argument, otherwise setuptools will raise an exception
-    sys.argv.remove('--cythonize')
+if True:
     try:
         # If Cython is installed, transpile the optimized Cython module to C and compile as a .pyd to be distributed
         from Cython.Build import cythonize, build_ext  # this acts as a check whether Cython is installed, otherwise this will fail