Issue #14738: Speed-up UTF-8 decoding on non-ASCII data.  Patch by Serhiy Storchaka.
diff --git a/Objects/stringlib/ucs4lib.h b/Objects/stringlib/ucs4lib.h
index eda0feb..647a27e 100644
--- a/Objects/stringlib/ucs4lib.h
+++ b/Objects/stringlib/ucs4lib.h
@@ -7,6 +7,7 @@
 #define STRINGLIB(F)             ucs4lib_##F
 #define STRINGLIB_OBJECT         PyUnicodeObject
 #define STRINGLIB_SIZEOF_CHAR    4
+#define STRINGLIB_MAX_CHAR       0x10FFFFu
 #define STRINGLIB_CHAR           Py_UCS4
 #define STRINGLIB_TYPE_NAME      "unicode"
 #define STRINGLIB_PARSE_CODE     "U"