i128 no_std

[zendurix]

README says that this crate supports no_std, however it depends on num-traits with i128 feature (even when run with no default features).
When I test some program that is dependand on num complex, with no-std-check (https://github.com/mystor/cargo-no-std-check)
I get this error: thread 'main' panicked at 'i128 support was not detected!

[cuviper]

I haven't seen cargo-no-std-check before, but it looks like it's using RUSTC_WRAPPER to intercept and rewrite target arguments. The autocfg crate will need to support this as well, otherwise feature detection is going to be broken in this use case. But in normal use, I expect it's still be fine.

There shouldn't be any real problem with i128 on no_std targets though. I have thought about relaxing those checks such that if the feature is requested, it will go ahead and be used without bothering to probe with autocfg.

[cuviper]

This should be fixed by num-traits 0.2.13 via rust-num/num-traits#185.
For the broader problem of RUSTC_WRAPPER, I'll leave that to cuviper/autocfg#26.