Index: PyYAML-6.0.1/setup.py
===================================================================
--- PyYAML-6.0.1.orig/setup.py
+++ PyYAML-6.0.1/setup.py
@@ -82,7 +82,11 @@ if 'sdist' in sys.argv or os.environ.get
     with_cython = True
 try:
     from Cython.Distutils.extension import Extension as _Extension
-    from Cython.Distutils import build_ext as _build_ext
+    try:
+         # try old_build_ext from Cython > 3 first, until we can dump it entirely
+         from Cython.Distutils.old_build_ext import old_build_ext as _build_ext
+    except ImportError:
+        from Cython.Distutils import build_ext as _build_ext
     with_cython = True
 except ImportError:
     if with_cython: