Issue 25483: Add an opcode to make f-string formatting more robust.
diff --git a/Include/ceval.h b/Include/ceval.h
index b5373a9..d194044 100644
--- a/Include/ceval.h
+++ b/Include/ceval.h
@@ -206,6 +206,14 @@
 PyAPI_FUNC(void) _PyEval_SignalAsyncExc(void);
 #endif
 
+/* Masks and values used by FORMAT_VALUE opcode. */
+#define FVC_MASK      0x3
+#define FVC_NONE      0x0
+#define FVC_STR       0x1
+#define FVC_REPR      0x2
+#define FVC_ASCII     0x3
+#define FVS_MASK      0x4
+#define FVS_HAVE_SPEC 0x4
 
 #ifdef __cplusplus
 }