Corrode should do something with _Static_assert

[lambdageek]

After #120 is accepted, language-c will parse _Static_assert successfully. In that PR, I just put in pattern match cases that just call error.

Probably the most important issue is that typeName in Language.Rust.Corrode.C should do something better with a static assert.

[jameysharp]

I'm pretty sure that @ranweiler and I today made typeName do the right thing for static asserts: I don't think those make any sense there so we made it call badSource, because I assume a real C compiler would report an error there too.

I'm not quite sure how to deal with a normal static assert as a declaration though. Does Rust have anything equivalent?