Issue #14738: Speed-up UTF-8 decoding on non-ASCII data.  Patch by Serhiy Storchaka.
diff --git a/Objects/stringlib/undef.h b/Objects/stringlib/undef.h
index 9310204..03117ec 100644
--- a/Objects/stringlib/undef.h
+++ b/Objects/stringlib/undef.h
@@ -1,6 +1,7 @@
 #undef  FASTSEARCH
 #undef  STRINGLIB
 #undef  STRINGLIB_SIZEOF_CHAR
+#undef  STRINGLIB_MAX_CHAR
 #undef  STRINGLIB_CHAR
 #undef  STRINGLIB_STR
 #undef  STRINGLIB_LEN