Please disregard this patch, it seems the proper change has been brought upstream, in icon version 3.5.1, to take in account the necessary change for GlibC 2.28:
http://www2.cs.arizona.edu/icon/current/
Said patch on upstream repository, for information:
https://github.com/gtownsend/icon/commit/bfc4a6004d0d3984c8066289b8d8e563640c4ddd
Kind Regards,
--
Étienne Mollier <etienne.moll...@mailoo.org>
