Replace transmuted references with explicit pointer type casts

[nickbeth]

Description

Rust docs about std::mem::transmute read:

Transmuting integers to pointers is a largely unspecified operation. It is likely not equivalent to an as cast. Doing non-zero-sized memory accesses with a pointer constructed this way is currently considered undefined behavior.

Source: https://doc.rust-lang.org/std/mem/fn.transmute.html#transmutation-between-pointers-and-integers

Although this library mostly transmutes to reference Dst types and not pointers, from my understanding the same rules apply for references as well. Additionally, code in the library sometimes transmutes to mutable references, which is even worse because strict aliasing rules may not be respected in that case.

Motivation

An issue was opened for my app, a Win32 GUI for WSL USB device management, reporting that release builds would crash at startup, with a STATUS_ILLEGAL_INSTRUCTION return code.
Upon further inspection, the issue boiled down to these transmutes [1] [2] in the tabs code. In that specific instance, UB was introduced, and for any opt-level > 0 the generated code would callq into a panic handler without a conditional jump before it, return from the handler and execute an ud2 instruction.

This was tested on Windows 11, Rust 1.82.0.

Change proposal

std::mem::transmute instances that would introduce UB are removed in favor of explicit type casts, and references are changed to pointers. There's many instances of std::mem::transmute being used incorrectly, this PR fixes all offending instances.

[JPHutchins]

May be some overlap in this PR: #250

[nickbeth]

Thanks @JPHutchins. It doesn't look like there should be any overlaps between the two PRs, as the changes are on different files. Also the impact of the other PR is none apart from code style changes.

[nickbeth]

Fixes #310.