Update to 3.7

[ewpratten]

work in progress

This PR will eventually close #80. For now, I am just using it to track my work.

[ewpratten]

Currently dealing with the following issue:

error[E0308]: mismatched types
  --> showcase/src/example/core/core_custom_logging.rs:42:43
   |
42 |             ffi::SetTraceLogCallback(Some(log_custom));
   |                                           ^^^^^^^^^^ expected struct `__va_list_tag`, found struct `va_list::VaList`
   |
   = note: expected fn pointer `unsafe extern "C" fn(_, _, *mut __va_list_tag)`
                 found fn item `extern "C" fn(_, _, *mut i8) {log_custom}`

This appears to be linked to rust-lang/rust#44930. Possibly just me missing something stupid. Either way, I'm looking for a workaround.

EDIT: It was the "me missing something stupid" answer. fixed

[ewpratten]

Alright. I have redone the bindgen bindings for Linux and OSX, but have run in to this issue: rust-lang/rust-bindgen#687

I have to switch projects right now anyways, since the end of LD48 is calling me.