Allow hermit-abi to build without std This makes crates depending on hermit-abi able to check their build by just using `-Zbuild-std=core` instead of needing all of `-Zbuild-std`. Also, remove an unnecessary feature that isn't used anywhere.
Allow hermit-abi to build without std This makes crates depending on hermit-abi able to check their build by just using `-Zbuild-std=core` instead of needing all of `-Zbuild-std`. Also, remove an unnecessary feature that isn't used anywhere.