Move `lib/support.rs` to zinc crate

As discussed in #106, this remove a bunch of functions that are no longer needed and only keeps the ones it doesn't compile with. It's been verified that there no symbols pulled into the ELFs from anywhere that would be the same as the ones removed by this change.
Actually, can you `#[doc(hidden)]` those other ones. If it is only the compiler calling them, there is no need to appear in documentation.