3.7 to 3.10 compatibility

setup.py

@@ -209,6 +209,8 @@ def run_uninstall(root_dir):
 
 class m_build_ext(build_ext):
     def run(self):
+        if USE_CYTHON:
+            remove_generated_c_file()
         root_dir = os.path.dirname(os.path.abspath(__file__))
         cur_dir = os.getcwd()
         run_cmake(root_dir)
@@ -316,10 +318,10 @@ def setup_package():
     # and build up the set of Extension objects
     if USE_CYTHON:
         fileExt = ".pyx"
-        remove_generated_c_file()
         print("Cython Used")
     else:
         fileExt = ".c"
+        print("witout Cython")
 
     extensions = [makeExtension(name, fileExt, lib_dir) for name in extNames]