Fixtype of type specifiers [C:6.7.3] [C:A.2.2].
This is a tagged union type, introduced by fty::deftagsum.
This captures type-specifier in the grammar in [C].
We model atomic-type-specifier
by inlining the type name into the
We make two separate cases for structures and unions, avoiding explicit modeling of the struct-or-union nonterminal.
We model typedef-name
by inlining the type name into the