closes bpo-35139: The `pyexpat` module's macros in `Modules/Setup` now match `setup.py` (GH-10289)

This could cause compile errors on macOS or other platforms.
diff --git a/Modules/Setup b/Modules/Setup
index c180463..e2b5f86 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -336,7 +336,7 @@
 # Interface to the Expat XML parser
 # More information on Expat can be found at www.libexpat.org.
 #
-#pyexpat expat/xmlparse.c expat/xmlrole.c expat/xmltok.c pyexpat.c -I$(srcdir)/Modules/expat -DHAVE_EXPAT_CONFIG_H -DUSE_PYEXPAT_CAPI
+#pyexpat expat/xmlparse.c expat/xmlrole.c expat/xmltok.c pyexpat.c -I$(srcdir)/Modules/expat -DHAVE_EXPAT_CONFIG_H -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI
 
 # Hye-Shik Chang's CJKCodecs