- convert to newer `..=` syntax, fixing compiler warnings

+ requires MinSRV >= v1.26.0

.# [why]

The inclusive range operator (`..=`) was stabilized in rust v1.26.0.

Warnings requesting conversion from the old `...` operator to `..=` were
introduced in rust v1.37.0.

* ref: <https://github.com/rust-lang/rust/blob/master/RELEASES.md>

- convert to newer `?` syntax, fixing compiler warnings

+ requires MinSRV >= v1.13.0

.# [why]

The `?` operator was stabilized in rust v1.13.0.

Warnings requesting conversion from the old `try!` macro to the `?` operator
were introduced in rust v1.39.0.

* ref: <https://github.com/rust-lang/rust/blob/master/RELEASES.md>

…t,end}...`

- `trim_{start,end}{,_matches}` stabilized in rust v1.30.0
- `trim_{start,end}{,_matches}` deprecated (with compiler warnings) in rust v1.33.0

+ requires MinSRV >= v1.30.0

* ref: https://github.com/rust-lang/rust/blob/master/RELEASES.md

- rust usually uses `assert_eq!(ACTUAL, EXPECTED)`
- ref: https://users.rust-lang.org/t/assert-eq-expected-and-actual/20304/3 @@ https://archive.is/xPp9R

…or testing

+ ToDO added ~ when possible, test under WSL2 and differentiate/liberalize if possible

…ions

- allow actual outputs to differ from expected (ie, `stat`) if `stat` is reporting "unknown" creation time

.# [why]

For many *nix flavors, `stat` is unable to detect birth/creation date
for directories/files. The information is available via the `statx()`
system call (for linux kernels >= v4.11), and rust supplies that
information via fs::MetadataExt for v1.40+. So, for rust v1.40+, there
will likely be a mismatch between the output of the system `stat` and
this ('uutils') `stat`.

* ref: <https://askubuntu.com/questions/470134/how-do-i-find-the-creation-time-of-a-file> @@ <https://archive.is/IsEAJ>

…at due to race conditions

.# [why]

`mem::ununitialized()` is deprecated as of rust v1.39.0.

And this use is likely a premature optimization attempting to avoid
initializing the byte array to 0, which is usually a *very* fast operation.

* ref: <https://github.com/rust-lang/rust/blob/master/RELEASES.md>
* ref: <https://stackoverflow.com/questions/3654905/faster-way-to-zero-memory-than-with-memset>

…ment)

…ing_as_ptr)

…level_ref_arg)

…in {for f64 comparisons})

…ames)

…ar_names)

.# [why]

Although `copied()` is preffered, it was not stabilized until rust v1.35.0.
So, 'map_clone' is allowed instead of increasing MinSRV to v1.35.0.

* ref: https://github.com/rust-lang/rust/blob/master/RELEASES.md

…_doc)

…; `clippy` bug workaround)

* ref: <rust-lang/rust-clippy#4898>

…eral {for dynamic code})

…_seq)

…::uninitialized)

.# [why]

`std::mem::MaybeUninit` is likely preffered. But `MaybeUninit` was not
stabilized until rust v1.36.0 and conversion from `mem::uninitialized` is
not obviously straight-forward at the moment.

So, 'std::mem::uninitialized' is allowed instead of increasing MinSRV to v1.36.0.

* ref: https://github.com/rust-lang/rust/blob/master/RELEASES.md