cargo rustc --bin imm-cee-tee-ess --release -- -C target-cpu=native --emit link=imm-cee-tee-ess-D8917C12
   Compiling arrayvec v0.7.6
   Compiling imm-cee-tee-ess v0.1.0 (/tmp/tmp87bamdpj/imm-cee-tee-ess/imm-cee-tee-ess-tmp)
error: `Option::<T>::unwrap` is not yet stable as a const fn
   --> src/fen.rs:175:18
    |
175 |     let column = vec[0].to_digit(20).unwrap() - 10;
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(const_option)]` to the crate attributes to enable

error: `Option::<T>::unwrap` is not yet stable as a const fn
   --> src/fen.rs:176:16
    |
176 |     let row = (vec[1].to_digit(10).unwrap() - 1) * 8;
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(const_option)]` to the crate attributes to enable

error: could not compile `imm-cee-tee-ess` (lib) due to 2 previous errors
make: *** [Makefile:10: openbench] Error 101