Type code generation for OTHER enum creates unnecessary struct

[zougloub]

Consider this:

root = {
 0 => indirect,
 1 => int,
}

indirect = int

which generates

struct root {
        int32_t indirect_m;
        int32_t uint1int;
};

Now, this:

root = {
 0: indirect,
 1: ((zero: 0) / (one: 1))
}

indirect = (
 (zero: 0) / (one: 1)
)

Again, the indirect type was defined in order to give a label to a structure field.
But this time, the generated code seems to be unnecessarily more verbose, creating:

struct indirect_r {
        enum {
                indirect_zero_c = 0,
                indirect_one_c = 1,
        } indirect_choice;
};

struct root {
        struct indirect_r indirect_m;
        enum {
                root_uint1union_zero_c = 0,
                root_uint1union_one_c = 1,
        } uint1union_choice;
};