https://bugs.gentoo.org/878395
--- a/bindings/cxx/enums.py
+++ b/bindings/cxx/enums.py
@@ -73,6 +73,8 @@
 code = open(os.path.join(outdirname, 'cxx/enums.cpp'), 'w')
 swig = open(os.path.join(outdirname, 'swig/enums.i'), 'w')
 
+print('%include "attribute.i" \n', file=swig)
+
 for file in (header, code):
     print("/* Generated file - edit enums.py instead! */", file=file)