Unfortunately, that yields an identical set of errors.
That's similar to how I did it at first. I prefixed the type declarations with 'struct' since I was having errors and hoped to be less ambiguous to the compiler.
I'm not terribly well grounded in C, which is why I feel like I'm missing something obvious. I could push the project (and its many tabs) to my github if that would make it easier to find the problem.
Thanks, though, for any and all suggestions.