https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61469
--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> --- There is a proposed enhancement for C2X to implement the ability to define the type to be used to represent an enum: <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2008.pdf>.