bpo-39882: Add _Py_FatalErrorFormat() function (GH-19157)

diff --git a/Include/cpython/pyerrors.h b/Include/cpython/pyerrors.h
index ab2e740..cdd0520 100644
--- a/Include/cpython/pyerrors.h
+++ b/Include/cpython/pyerrors.h
@@ -182,6 +182,11 @@
     const char *func,
     const char *message);
 
+PyAPI_FUNC(void) _Py_NO_RETURN _Py_FatalErrorFormat(
+    const char *func,
+    const char *format,
+    ...);
+
 #define Py_FatalError(message) _Py_FatalErrorFunc(__func__, message)
 
 #ifdef __cplusplus