While this is true, I don't see either a reason to use _t in your code. Since it's your code, you don't have the problem for which the _t suffix was introduced, that is to avoid conflicts that can break other people code. You don't either get any benefit of using the _t suffix, since it's obvious if something is a type or not, especially nowadays (just look at the syntax coloring). You don't even need the _t to distinguish for example between a struct, enum or union definition and it's relative typedef:

    typedef struct MyStruct { ... } MyStruct;

is perfectly valid, and in my opinion better than:

    typedef struct MyStruct_s { ... } MyStruct_t;

Where the suffix _s and _t doesn't add anything useful but only complicate the code for nothing.