Rollup of 8 pull requests

[frewsxcv]

• Successful merges: Forward more Iterator methods #43074, fail in case nothing to run was found #43145, Disable big-endian simd in swap_nonoverlapping_bytes #43159, Fix sys::redox::net::tcp #43202, windows::fs::symlink_dir: fix example to actually use symlink_dir #43222, Fix backtrace on Redox #43228, Fix minor typo in std::path documentation. #43229, Update the books. #43240
• Failed merges:

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @alexcrichton (or someone else) soon.

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[frewsxcv]

@bors r+ p=10

[bors]

📌 Commit e3825ec has been approved by frewsxcv

[bors]

⌛ Testing commit e3825ec with merge aadab827b13792f3156c8fe3b3481460acc5860c...

[bors]

💔 Test failed - status-travis

[kennytm]

dist-i586-gnu-i686-musl failed at slice::test_box_slice_clone_panics. Maybe spurious? Since threads and atomic are involved this may be a musl bug.

[01:21:56] test slice::test_capacity ... ok
[01:21:56] test slice::test_chunksator ... ok
[01:21:56] test slice::test_chunksator_0 ... ok
[01:21:56] thread '<unnamed>' panicked at 'explicit panic', /checkout/src/liballoc/../liballoc/tests/slice.rs:1194:16
[01:21:56] test slice::test_concat ... ok
[01:21:56] �(B�[m�[31m�[1merror:�(B�[m An unknown error occurred
[01:21:56] �(B�[m
[01:21:56] To learn more, run the command again with --verbose.
[01:21:56] 
[01:21:56] 
[01:21:56] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "test" "-j" "4" "--target" "i686-unknown-linux-musl" "--release" "--locked" "--color" "always" "--manifest-path" "/checkout/src/libstd/Cargo.toml" "--features" "panic-unwind jemalloc backtrace" "-p" "std:0.0.0" "-p" "alloc:0.0.0" "-p" "compiler_builtins:0.0.0" "-p" "unwind:0.0.0" "-p" "core:0.0.0" "-p" "std_unicode:0.0.0" "-p" "libc:0.0.0" "-p" "alloc_system:0.0.0" "-p" "rustc_lsan:0.0.0" "-p" "rustc_asan:0.0.0" "-p" "panic_abort:0.0.0" "-p" "rustc_msan:0.0.0" "-p" "collections:0.0.0" "-p" "rustc_tsan:0.0.0" "-p" "rand:0.0.0" "--"
[01:21:56] expected success, got: exit code: 101
[01:21:56] 
[01:21:56] 
[01:21:56] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --target i686-unknown-linux-musl --target i586-unknown-linux-gnu
[01:21:56] Build completed unsuccessfully in 1:20:21
[01:21:56] �(B�[m

Line 1194 of slice.rs:

#[test]
#[cfg_attr(target_os = "emscripten", ignore)]
fn test_box_slice_clone_panics() {
    use std::sync::Arc;
    use std::sync::atomic::{AtomicUsize, Ordering};
    use std::thread::spawn;

    struct Canary {
        count: Arc<AtomicUsize>,
        panics: bool,
    }

    impl Drop for Canary {
        fn drop(&mut self) {
            self.count.fetch_add(1, Ordering::SeqCst);
        }
    }

    impl Clone for Canary {
        fn clone(&self) -> Self {
            if self.panics {
                panic!()      // <---------------------------- line 1194
            }

            Canary {
                count: self.count.clone(),
                panics: self.panics,
            }
        }
    }

    let drop_count = Arc::new(AtomicUsize::new(0));
    let canary = Canary {
        count: drop_count.clone(),
        panics: false,
    };
    let panic = Canary {
        count: drop_count.clone(),
        panics: true,
    };

    spawn(move || {
            // When xs is dropped, +5.
            let xs = vec![canary.clone(), canary.clone(), canary.clone(), panic, canary]
                .into_boxed_slice();

            // When panic is cloned, +3.
            xs.clone();
        })
        .join()
        .unwrap_err();

    // Total = 8
    assert_eq!(drop_count.load(Ordering::SeqCst), 8);
}

[steveklabnik]

@bors: retry

given that travis passed, yes, I'm guessing this is spurious

[bors]

⌛ Testing commit e3825ec with merge a783fe2...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: frewsxcv
Pushing a783fe2 to master...