merge 3.3 (#19186)

Misc/NEWS

@@ -24,6 +24,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #19186: Restore namespacing of expat symbols inside the pyexpat module.
+
 - Issue #20053: ensurepip (and hence venv) are no longer affected by the
   settings in the default pip configuration file.
 

Modules/expat/expat_external.h

@@ -7,6 +7,10 @@
 
 /* External API definitions */
 
+/* Namespace external symbols to allow multiple libexpat version to
+   co-exist. */
+#include "pyexpatns.h"
+
 #if defined(_MSC_EXTENSIONS) && !defined(__BEOS__) && !defined(__CYGWIN__)
 #define XML_USE_MSC_EXTENSIONS 1
 #endif