Add verbose debugging version reporting

[chrissimpkins]

Adds a new --vv option for verbose debugging version reporting of:

• fontc version + git commit SHA hash
• rustc host triple
• rustc version + toolchain channel + short git commit SHA hash + commit date
• llvm version
• cargo profile (release / debug)
• cargo optimization level

Adds a new fontc package vergen build dependency and build.rs file to set the environment variables required to define these strings at build time. Should continue to support deterministic builds with the data fields that I've included in this report.

Example output:

cargo nightly release build

$ target/release/fontc --vv
fontc 0.0.1 @ 39104650dd31603be7b97a169c468c39bc0e5674

x86_64-apple-darwin
rustc 1.76.0-nightly (channel: nightly, 3a85a5cfe 2023-11-20)
llvm 17.0
cargo profile: release
cargo optimization level: 3

GitHub UI formatting as pasted into the tracker:

fontc 0.0.1 @ 3910465

x86_64-apple-darwin
rustc 1.76.0-nightly (channel: nightly, 3a85a5cfe 2023-11-20)
llvm 17.0
cargo profile: release
cargo optimization level: 3

cargo stable debug build

$ target/debug/fontc --vv
fontc 0.0.1 @ 39104650dd31603be7b97a169c468c39bc0e5674

x86_64-apple-darwin
rustc 1.74.0 (channel: stable, 79e9716c9 2023-11-13)
llvm 17.0
cargo profile: debug
cargo optimization level: 0

GitHub UI formatting as pasted into the tracker:

fontc 0.0.1 @ 3910465

x86_64-apple-darwin
rustc 1.74.0 (channel: stable, 79e9716c9 2023-11-13)
llvm 17.0
cargo profile: debug
cargo optimization level: 0

[chrissimpkins]

We don't like the println! macro?

Error: The following Rust source files contain println! or eprintln! statements:
fontc/src/main.rs:[9](https://github.com/googlefonts/fontc/actions/runs/6938594342/job/18874561283?pr=590#step:7:10)5:     println!(
fontc/src/main.rs:101:     println!("{}", env!("VERGEN_RUSTC_HOST_TRIPLE"));
fontc/src/main.rs:102:     println!(
fontc/src/main.rs:[10](https://github.com/googlefonts/fontc/actions/runs/6938594342/job/18874561283?pr=590#step:7:11)7:     println!("llvm {}", env!("VERGEN_RUSTC_LLVM_VERSION"));
fontc/src/main.rs:109:         "true" => println!("cargo profile: debug"),
fontc/src/main.rs:[11](https://github.com/googlefonts/fontc/actions/runs/6938594342/job/18874561283?pr=590#step:7:12)0:         "false" => println!("cargo profile: release"),
fontc/src/main.rs:113:     println!(
Please remove or comment out the println! and eprintln! statements before pushing.
Error: Process completed with exit code 1.

[chrissimpkins]

We don't like the println! macro?

Fixed with conversion to writeln! and error propagation in 583a8da

[cmyr]

This looks like it should be useful, thanks!

[anthrotype]

nice, thanks!