bpo-40334: PEP 617 implementation: New PEG parser for CPython (GH-19503)

Co-authored-by: Guido van Rossum <guido@python.org>
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
diff --git a/Include/cpython/initconfig.h b/Include/cpython/initconfig.h
index c5fa2b3..6539596 100644
--- a/Include/cpython/initconfig.h
+++ b/Include/cpython/initconfig.h
@@ -147,6 +147,10 @@
        Set to 1 by -X faulthandler and PYTHONFAULTHANDLER. -1 means unset. */
     int faulthandler;
 
+    /* Enable PEG parser?
+       1 by default, set to 0 by -X oldparser and PYTHONOLDPARSER */
+    int use_peg;
+
     /* Enable tracemalloc?
        Set by -X tracemalloc=N and PYTHONTRACEMALLOC. -1 means unset */
     int tracemalloc;