[3.14] gh-135755: Use private names (_Py*) for header file guards new in 3.14 (GH-135921) (GH-135976)

These are private API; let's name new ones accordingly.
(cherry picked from commit 6be17baeb5)

Co-authored-by: Petr Viktorin <encukou@gmail.com>

Include/audit.h

@@ -1,5 +1,5 @@
-#ifndef Py_AUDIT_H
-#define Py_AUDIT_H
+#ifndef _Py_AUDIT_H
+#define _Py_AUDIT_H
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -18,13 +18,13 @@ PyAPI_FUNC(int) PySys_AuditTuple(
 
 
 #ifndef Py_LIMITED_API
-#  define Py_CPYTHON_AUDIT_H
+#  define _Py_CPYTHON_AUDIT_H
 #  include "cpython/audit.h"
-#  undef Py_CPYTHON_AUDIT_H
+#  undef _Py_CPYTHON_AUDIT_H
 #endif
 
 
 #ifdef __cplusplus
 }
 #endif
-#endif /* !Py_AUDIT_H */
+#endif /* !_Py_AUDIT_H */

Include/cpython/audit.h

@@ -1,4 +1,4 @@
-#ifndef Py_CPYTHON_AUDIT_H
+#ifndef _Py_CPYTHON_AUDIT_H
 #  error "this header file must not be included directly"
 #endif
 

Include/refcount.h

@@ -1,5 +1,5 @@
-#ifndef Py_REFCOUNT_H
-#define Py_REFCOUNT_H
+#ifndef _Py_REFCOUNT_H
+#define _Py_REFCOUNT_H
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -564,4 +564,4 @@ static inline PyObject* _Py_XNewRef(PyObject *obj)
 #ifdef __cplusplus
 }
 #endif
-#endif   // !Py_REFCOUNT_H
+#endif   // !_Py_REFCOUNT_H