- more precisely describe permissable libc versions
.# [why]
- libc >= v0.2.15 is needed for utmp support.
- libc <= v0.2.66 is required to avoid build errors for MinSRV == 1.31.0.
Intermittant build failures were being caused by `cargo` using early libc versions.
- hold data-encoding to known working "<= 2.1.2"
.# [why]
data-encoding v2.2.0 causes a build error for '1.31.0-i686-pc-windows-msvc'.
```
cargo +1.31.0-i686-pc-windows-msvc build --target=i686-pc-windows-msvc --all-features
...
error[E0658]: imports can only refer to extern crate names passed with `--extern` on stable channel (see issue #53130)
--> C:\Users\appveyor\.cargo\registry\src\github.com-1ecc6299db9ec823\data-encoding-2.2.0\src\lib.rs:194:5
|
187 | / mod prelude {
188 | | pub use std::borrow::Cow;
189 | | }
| |_- not an extern crate passed with `--extern`
...
194 | use prelude::*;
| ^^^^^^^
|
...
```
. #[why]
Technically, by semver rules, projects with versions < v1.0.0 may make breaking
changes with *any* version change. So, for some protection, pin all crates with
version < v1.0.0 to a specific version.
* ref: <https://semver.org> @@ <https://archive.is/LTGHB>
- hotfix transitive bug in 'failure' forcing MinSRV increase to rust v1.33.0 by pinning 'backtrace' to <= 0.3.31
- [rustlang/nursery#340](https://github.com/rust-lang-nursery/failure/issues/340) is now open on 'failure' to address this issue
.# [why]
'failure' was using 'backtrace' `version = "0.3.3"`, which by semantic version
auto-upgrade was pulling in 'backtrace' > v0.3.30 (specifically, v0.3.40 most
recently). 'backtrace' v0.3.31 introduces use of `#[cfg(target_vendor = ...)]`
which requires rust v1.33.0. So, 'backtrace' is forcing an upgrade of MinSRV
to rust v1.33.0 with the change from backtrace v0.3.30 to backtrace v0.3.31.
Technically, by being less than v1.0.0, 'backtrace' has no semantic version
requirement. And there is debate about whether increasing MinSRV is a semantic
change. But, in my strong opinion, breaking our MinSRV statement is definitely
a semantic change.
* ref: <https://github.com/rust-lang/rust/blob/master/RELEASES.md>
- standardize the return value of `std::env::current_dir()` by using `canonicalize()`
.# [why]
`std::env::current_dir()` will, in some situations on windows hosts, return
"short"-type paths (eg, "C:\Progra~1\..."). Using `canonicalize()` transforms
the path in a standard long form but may also require removing a leading
"\\?\" prefix.
