Nonstarter based on ring dependency

[tvquizphd]

error[E0658]: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead?
   --> /root/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/ring-0.16.20/src/rand.rs:218:30
    |
218 |         const SYS_GETRANDOM: c_long = 318;
    |                              ^^^^^^
    |
    = note: see issue #27812 <https://github.com/rust-lang/rust/issues/27812> for more information
    = help: add `#![feature(rustc_private)]` to the crate attributes to enable

rust-lang/rust#27812

If you're using a stable or a beta version of rustc, you won't be able to use
any unstable features. In order to do so, please switch to a nightly version of
rustc (by using [rustup]).

If you're using a nightly version of rustc, just add the corresponding feature
to be able to use it:

from rustc --explain E0658