Fix LibAFL no_std errors when compiling for baremetal/embedded targets without libc/unix

[YungRaj]

Fix this error when compiling with no_std for e.g. baremetal and embedded targets

error[E0433]: cannot find module or crate `libc` in this scope
   --> /Users/ilhanraja/.cargo/git/checkouts/libafl-df9415290f13ce43/ee91ab6/crates/libafl_bolts/src/os.rs:109:14
    |
109 |             *libc::__error()
    |              ^^^^ use of unresolved module or unlinked crate `libc`
    |
    = help: if you wanted to use a crate named `libc`, use `cargo add libc` to add it to your `Cargo.toml`

For more information about this error, try `rustc --explain E0433`.
error: could not compile `libafl_bolts` (lib) due to 1 previous error

[domenukk]

This is already:

#[cfg(all(
    not(feature = "std"),
    any(
        target_os = "linux",
        target_os = "android",
        target_os = "macos",
        target_os = "freebsd",
        target_os = "dragonfly",
        target_os = "openbsd",
        target_os = "netbsd"
    )
))]

are you using macos for kernel?

[YungRaj]

This is already:

#[cfg(all(
    not(feature = "std"),
    any(
        target_os = "linux",
        target_os = "android",
        target_os = "macos",
        target_os = "freebsd",
        target_os = "dragonfly",
        target_os = "openbsd",
        target_os = "netbsd"
    )
))]

are you using macos for kernel?

Yes I am using macOS for kernel so that the target triple when compiling is correct.

[YungRaj]

Looks like the recent changes worked.