[3.10] bpo-46521: Fix codeop to use a new partial-input mode of the parser (GH-31010). (GH-31213)

(cherry picked from commit 69e10976b2e7682c6d57f4272932ebc19f8e8859)

Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
diff --git a/Parser/pegen.h b/Parser/pegen.h
index 29d4805..bf58f1e 100644
--- a/Parser/pegen.h
+++ b/Parser/pegen.h
@@ -22,6 +22,7 @@
 #define PyPARSE_BARRY_AS_BDFL 0x0020
 #define PyPARSE_TYPE_COMMENTS 0x0040
 #define PyPARSE_ASYNC_HACKS   0x0080
+#define PyPARSE_ALLOW_INCOMPLETE_INPUT 0x0100
 
 typedef struct _memo {
     int type;