Clean _generated.h files

setup.py

@@ -1406,7 +1406,7 @@ def clean() -> None:
             dirs.remove(d)
         for f in files:
             ext = f.rpartition('.')[-1]
-            if ext in ('so', 'dylib', 'pyc', 'pyo'):
+            if ext in ('so', 'dylib', 'pyc', 'pyo') or f.endswith('_generated.h'):
                 os.unlink(os.path.join(root, f))
     for x in glob.glob('glfw/wayland-*-protocol.[ch]'):
         os.unlink(x)