Add -frust-very-long flag to CI

[CohenArthur]

Otherwise this causes the CI to consistently fail.

[Taym95]

Hi, can you point me where CI config are, I can pick it up, thanks

[bjorn3]

https://github.com/Rust-GCC/cargo-gccrs/blob/main/.github/workflows/fmt_build_tests.yml

[CohenArthur]

@Taym95 the actual flag isn't -frust-very-long, I thought I'd be the one taking care of this :) you an look at the CI failure on your PR to see what it should look like exactly. It should be

-frust-incomplete-and-experimental-compiler-do-not-use

And I believe you might need to change some code in cargo-gccrs as well to handle GCCRS_EXTRA_FLAGS as an environment variable instead of GCC_EXTRA_FLAGS. I can't remember exactly where that happens but can point it to you soon

[Taym95]

@CohenArthur Ah okay you can take care of it, I will keep eye on your implementation to learn from it!