diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index 3cd647b..1aaaa28 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -37,8 +37,12 @@
 # different (hard-wired) directories.
 # Setup.local is available for Makefile builds including VPATH builds,
 # Setup.dist is available on Windows
-python_build = any(os.path.isfile(os.path.join(project_base, "Modules", fn))
-                   for fn in ("Setup.dist", "Setup.local"))
+def _python_build():
+    for fn in ("Setup.dist", "Setup.local"):
+        if os.path.isfile(os.path.join(project_base, "Modules", fn)):
+            return True
+    return False
+python_build = _python_build()
 
 
 def get_python_version():