Auto merge of #2460 - LegNeato:sysconf, r=RalfJung
Auto merge of #2460 - LegNeato:sysconf, r=RalfJung

Add additional raw error mappings for the nightly `io_error_more` feature

Some crates are using nightly and failing when mapping these errors,
for example <https://miri.saethlin.dev/?crate=remove_dir_all&version=0.7.0>:

```
error: unsupported operation: io error NotADirectory cannot be translated into a raw os error
    --> /root/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/sys/unix/fs.rs:1203:19
```

rust-lang/miri,rust-lang/miri,rust-lang/miri,rust-lang/miri