Add PyUnicode_Copy() function, include it to the public API
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index a2c07f5..9f3f66d 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -510,6 +510,11 @@
     );
 #endif
 
+/* Get a copy of a Unicode string. */
+PyAPI_FUNC(PyObject*) PyUnicode_Copy(
+    PyObject *unicode
+    );
+
 /* Copy character from one unicode object into another, this function performs
    character conversion when necessary and falls back to memcpy if possible.