bpo-37253: Add _PyCompilerFlags_INIT macro (GH-14018)


Add a new _PyCompilerFlags_INIT macro to initialize PyCompilerFlags
variables, rather than initializing cf_flags and cf_feature_version
explicitly in each variable.
(cherry picked from commit 37d66d7d4bc7dbac9809d69966a774ebb32563be)

Co-authored-by: Victor Stinner <vstinner@redhat.com>
diff --git a/Include/compile.h b/Include/compile.h
index a833caa..1cda955 100644
--- a/Include/compile.h
+++ b/Include/compile.h
@@ -30,6 +30,9 @@
     int cf_flags;  /* bitmask of CO_xxx flags relevant to future */
     int cf_feature_version;  /* minor Python version (PyCF_ONLY_AST) */
 } PyCompilerFlags;
+
+#define _PyCompilerFlags_INIT \
+    (PyCompilerFlags){.cf_flags = 0, .cf_feature_version = PY_MINOR_VERSION}
 #endif
 
 /* Future feature support */