Don't traverse through special-cased <stdint.h> types.

[goffrie]

Fixes #1663.

Not sure if this is too special-casey, but there's already a bunch of this stuff strewn about. Seems like it would be cleanest to add a new TypeKind for stdint types populated in from_clang_ty but that seemed like a ton of work for relatively little gain.

[pvdrz]

Thanks for your PR!

I tried to do a mini test about this using b5ec18e and found that:

typedef unsigned long long uint64_t;

uint64_t foo();

emits the following rust code:

/* automatically generated by rust-bindgen 0.60.1 */

extern "C" {
    pub fn foo() -> u64;
}

Do you have an extra example showing how your changes affect this behavior so we can add it as a test?

[goffrie]

I added a test that demonstrates the issue. The key is to have a two-layer typedef: typedef unsigned long long __uint64_t; typedef __uint64_t uint64_t;
Without this PR, an extraneous type __uint64_t = ::std::os::raw::c_ulonglong; is emitted.

[pvdrz]

Looks good to me! Thanks!