Issue #8715: Create PyUnicode_EncodeFSDefault() function: Encode a Unicode
object to Py_FileSystemDefaultEncoding with the "surrogateescape" error
handler, return a bytes object. If Py_FileSystemDefaultEncoding is not set,
fall back to UTF-8.
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 383187b..ddc9000 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -1268,6 +1268,16 @@
     Py_ssize_t size              /* size */
     );
 
+/* Encode a Unicode object to Py_FileSystemDefaultEncoding with the
+   "surrogateescape" error handler, return a bytes object.
+
+   If Py_FileSystemDefaultEncoding is not set, fall back to UTF-8.
+*/
+
+PyAPI_FUNC(PyObject*) PyUnicode_EncodeFSDefault(
+    PyObject *unicode
+    );
+
 /* --- Methods & Slots ----------------------------------------------------
 
    These are capable of handling Unicode objects and strings on input