Add more posix message queue functions for Linux and all for solarish

I'm not able to run the tests locally (likely due to too old headers on Ubuntu 18.04), but I've tested my [posixmq crate](https://github.com/tormol/posixmq/tree/0decb7c82dd472024c7e90fd8121671881a81ae2) with these functions on Linux and OmniOS.

Refactor the GNU module

Rename the notbsd module to linux_like

Upgrade rlimit consts

cc @aidanhs - this should fix the error you are seeing.

Fix type of RLIMIT consts on linux gnu

Add missing TIOCGRS485, TIOCSRS485 constants to Linux

Closes #1094 .

Deprecate fixed width integer type aliases

cc @emilio - I think it makes sense to ensure that the latest released version of bindgen works properly with this change. That is, that even when asked to use C types from, e.g., `libc::`, it does not use aliases for the fixed-width integer C types (e.g. `libc::int64_t`) but uses Rust primitive types instead (e.g. `u64`).

Closes #1304 .

Add statx on Linux

Closes #1178.

Deprecate AF_MAX and PF_MAX

Closes #1094 .

Closes #1304 .

Closes #1178.