Auto merge of #39638 - frewsxcv:rollup, r=frewsxcv

Rollup of 13 pull requests

- Successful merges: #38764, #39361, #39372, #39374, #39400, #39426, #39431, #39459, #39482, #39545, #39593, #39620, #39621
- Failed merges:

15 files changed, 52 insertions, 100 deletions

diff --git a/src/libstd/build.rs b/src/libstd/build.rs
index a0844821709..0fca374f6e6 100644
--- a/src/libstd/build.rs
+++ b/src/libstd/build.rs
@@ -21,7 +21,6 @@ use std::process::Command;
 use build_helper::{run, rerun_if_changed_anything_in_dir, up_to_date};
 
 fn main() {
-    println!("cargo:rustc-cfg=cargobuild");
     println!("cargo:rerun-if-changed=build.rs");
 
     let target = env::var("TARGET").expect("TARGET was not set");
diff --git a/src/libstd/env.rs b/src/libstd/env.rs
index 29f2ac6ab44..e2641539294 100644
--- a/src/libstd/env.rs
+++ b/src/libstd/env.rs
@@ -24,16 +24,19 @@ use path::{Path, PathBuf};
 use sys;
 use sys::os as os_imp;
 
-/// Returns the current working directory as a `PathBuf`.
+/// Returns the current working directory as a [`PathBuf`].
 ///
 /// # Errors
 ///
-/// Returns an `Err` if the current working directory value is invalid.
+/// Returns an [`Err`] if the current working directory value is invalid.
 /// Possible cases:
 ///
 /// * Current directory does not exist.
 /// * There are insufficient permissions to access the current directory.
 ///
+/// [`PathBuf`]: ../../std/path/struct.PathBuf.html
+/// [`Err`]: ../../std/result/enum.Result.html#method.err
+///
 /// # Examples
 ///
 /// ```
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 1f3526e1a09..3a552c060a9 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -464,9 +464,6 @@ mod panicking;
 mod rand;
 mod memchr;
 
-// This module just defines per-platform native library dependencies
-mod rtdeps;
-
 // The runtime entry point and a few unstable public functions used by the
 // compiler
 pub mod rt;
diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
index 751878c687c..84c4acb8d92 100644
--- a/src/libstd/net/addr.rs
+++ b/src/libstd/net/addr.rs
@@ -456,6 +456,13 @@ impl From<SocketAddrV6> for SocketAddr {
     }
 }
 
+#[stable(feature = "addr_from_into_ip", since = "1.17.0")]
+impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
+    fn from(pieces: (I, u16)) -> SocketAddr {
+        SocketAddr::new(pieces.0.into(), pieces.1)
+    }
+}
+
 impl<'a> IntoInner<(*const c::sockaddr, c::socklen_t)> for &'a SocketAddr {
     fn into_inner(self) -> (*const c::sockaddr, c::socklen_t) {
         match *self {
diff --git a/src/libstd/net/ip.rs b/src/libstd/net/ip.rs
index 3dc89e390ee..5d6e8d319d7 100644
--- a/src/libstd/net/ip.rs
+++ b/src/libstd/net/ip.rs
@@ -656,6 +656,13 @@ impl From<[u8; 4]> for Ipv4Addr {
     }
 }
 
+#[stable(feature = "ip_from_slice", since = "1.17.0")]
+impl From<[u8; 4]> for IpAddr {
+    fn from(octets: [u8; 4]) -> IpAddr {
+        IpAddr::V4(Ipv4Addr::from(octets))
+    }
+}
+
 impl Ipv6Addr {
     /// Creates a new IPv6 address from eight 16-bit segments.
     ///
@@ -1186,6 +1193,21 @@ impl From<[u16; 8]> for Ipv6Addr {
     }
 }
 
+
+#[stable(feature = "ip_from_slice", since = "1.17.0")]
+impl From<[u8; 16]> for IpAddr {
+    fn from(octets: [u8; 16]) -> IpAddr {
+        IpAddr::V6(Ipv6Addr::from(octets))
+    }
+}
+
+#[stable(feature = "ip_from_slice", since = "1.17.0")]
+impl From<[u16; 8]> for IpAddr {
+    fn from(segments: [u16; 8]) -> IpAddr {
+        IpAddr::V6(Ipv6Addr::from(segments))
+    }
+}
+
 // Tests for this module
 #[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
diff --git a/src/libstd/panicking.rs b/src/libstd/panicking.rs
index e5edea241e1..d76e8816ca4 100644
--- a/src/libstd/panicking.rs
+++ b/src/libstd/panicking.rs
@@ -311,12 +311,12 @@ impl<'a> Location<'a> {
 }
 
 fn default_hook(info: &PanicInfo) {
-    #[cfg(any(not(cargobuild), feature = "backtrace"))]
+    #[cfg(feature = "backtrace")]
     use sys_common::backtrace;
 
     // If this is a double panic, make sure that we print a backtrace
     // for this panic. Otherwise only print it if logging is enabled.
-    #[cfg(any(not(cargobuild), feature = "backtrace"))]
+    #[cfg(feature = "backtrace")]
     let log_backtrace = {
         let panics = update_panic_count(0);
 
@@ -341,7 +341,7 @@ fn default_hook(info: &PanicInfo) {
         let _ = writeln!(err, "thread '{}' panicked at '{}', {}:{}",
                          name, msg, file, line);
 
-        #[cfg(any(not(cargobuild), feature = "backtrace"))]
+        #[cfg(feature = "backtrace")]
         {
             use sync::atomic::{AtomicBool, Ordering};
 
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index eb0a6cd74d7..07b43cd89ac 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -1265,6 +1265,13 @@ impl Borrow<Path> for PathBuf {
     }
 }
 
+#[stable(feature = "default_for_pathbuf", since = "1.16.0")]
+impl Default for PathBuf {
+    fn default() -> Self {
+        PathBuf::new()
+    }
+}
+
 #[stable(feature = "cow_from_path", since = "1.6.0")]
 impl<'a> From<&'a Path> for Cow<'a, Path> {
     #[inline]
diff --git a/src/libstd/rtdeps.rs b/src/libstd/rtdeps.rs
deleted file mode 100644
index 5dc6ee2bc8c..00000000000
--- a/src/libstd/rtdeps.rs
+++ /dev/null
@@ -1,68 +0,0 @@
-// Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! This module contains the linkage attributes to all runtime dependencies of
-//! the standard library This varies per-platform, but these libraries are
-//! necessary for running libstd.
-
-#![cfg(not(cargobuild))]
-
-// LLVM implements the `frem` instruction as a call to `fmod`, which lives in
-// libm. Hence, we must explicitly link to it.
-//
-// On Linux, librt and libdl are indirect dependencies via std,
-// and binutils 2.22+ won't add them automatically
-#[cfg(all(target_os = "linux", not(target_env = "musl")))]
-#[link(name = "dl")]
-#[link(name = "pthread")]
-extern {}
-
-#[cfg(target_os = "android")]
-#[link(name = "dl")]
-#[link(name = "log")]
-extern {}
-
-#[cfg(target_os = "freebsd")]
-#[link(name = "execinfo")]
-#[link(name = "pthread")]
-extern {}
-
-#[cfg(any(target_os = "dragonfly",
-          target_os = "bitrig",
-          target_os = "netbsd",
-          target_os = "openbsd"))]
-#[link(name = "pthread")]
-extern {}
-
-#[cfg(target_os = "solaris")]
-#[link(name = "socket")]
-#[link(name = "posix4")]
-#[link(name = "pthread")]
-extern {}
-
-// For PNaCl targets, nacl_io is a Pepper wrapper for some IO functions
-// missing (ie always error) in Newlib.
-#[cfg(all(target_os = "nacl", not(test)))]
-#[link(name = "nacl_io", kind = "static")]
-#[link(name = "c++", kind = "static")] // for `nacl_io` and EH.
-#[link(name = "pthread", kind = "static")]
-extern {}
-
-#[cfg(target_os = "macos")]
-#[link(name = "System")]
-extern {}
-
-#[cfg(target_os = "ios")]
-#[link(name = "System")]
-extern {}
-
-#[cfg(target_os = "haiku")]
-#[link(name = "network")]
-extern {}
diff --git a/src/libstd/sys/unix/args.rs b/src/libstd/sys/unix/args.rs
index 0f447ff4ec4..6e35a472792 100644
--- a/src/libstd/sys/unix/args.rs
+++ b/src/libstd/sys/unix/args.rs
@@ -189,11 +189,6 @@ mod imp {
             fn objc_msgSend_ul(obj: NsId, sel: Sel, ...) -> NsId;
         }
 
-        #[link(name = "Foundation", kind = "framework")]
-        #[link(name = "objc")]
-        #[cfg(not(cargobuild))]
-        extern {}
-
         type Sel = *const libc::c_void;
         type NsId = *const libc::c_void;
 
diff --git a/src/libstd/sys/unix/mod.rs b/src/libstd/sys/unix/mod.rs
index fd7dc17cccd..c57751a01d7 100644
--- a/src/libstd/sys/unix/mod.rs
+++ b/src/libstd/sys/unix/mod.rs
@@ -33,7 +33,7 @@ pub mod weak;
 
 pub mod args;
 pub mod android;
-#[cfg(any(not(cargobuild), feature = "backtrace"))]
+#[cfg(feature = "backtrace")]
 pub mod backtrace;
 pub mod condvar;
 pub mod env;
diff --git a/src/libstd/sys/unix/process/process_common.rs b/src/libstd/sys/unix/process/process_common.rs
index 3497b266340..a4536520376 100644
--- a/src/libstd/sys/unix/process/process_common.rs
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -439,6 +439,10 @@ mod tests {
     #[test]
     #[cfg_attr(target_os = "macos", ignore)]
     #[cfg_attr(target_os = "nacl", ignore)] // no signals on NaCl.
+    // When run under our current QEMU emulation test suite this test fails,
+    // although the reason isn't very clear as to why. For now this test is
+    // ignored there.
+    #[cfg_attr(target_arch = "arm", ignore)]
     fn test_process_mask() {
         unsafe {
             // Test to make sure that a signal mask does not get inherited.
@@ -471,7 +475,7 @@ mod tests {
             // Either EOF or failure (EPIPE) is okay.
             let mut buf = [0; 5];
             if let Ok(ret) = stdout_read.read(&mut buf) {
-                assert!(ret == 0);
+                assert_eq!(ret, 0);
             }
 
             t!(cat.wait());
diff --git a/src/libstd/sys/unix/rand.rs b/src/libstd/sys/unix/rand.rs
index 9b1cf6ffd0e..77ebad4e344 100644
--- a/src/libstd/sys/unix/rand.rs
+++ b/src/libstd/sys/unix/rand.rs
@@ -257,10 +257,6 @@ mod imp {
     #[allow(non_upper_case_globals)]
     const kSecRandomDefault: *const SecRandom = ptr::null();
 
-    #[link(name = "Security", kind = "framework")]
-    #[cfg(not(cargobuild))]
-    extern {}
-
     extern {
         fn SecRandomCopyBytes(rnd: *const SecRandom,
                               count: size_t, bytes: *mut u8) -> c_int;
diff --git a/src/libstd/sys/windows/c.rs b/src/libstd/sys/windows/c.rs
index 850d6f49612..e5010ca3564 100644
--- a/src/libstd/sys/windows/c.rs
+++ b/src/libstd/sys/windows/c.rs
@@ -833,13 +833,6 @@ pub struct CONSOLE_READCONSOLE_CONTROL {
 }
 pub type PCONSOLE_READCONSOLE_CONTROL = *mut CONSOLE_READCONSOLE_CONTROL;
 
-#[link(name = "ws2_32")]
-#[link(name = "userenv")]
-#[link(name = "shell32")]
-#[link(name = "advapi32")]
-#[cfg(not(cargobuild))]
-extern {}
-
 extern "system" {
     pub fn WSAStartup(wVersionRequested: WORD,
                       lpWSAData: LPWSADATA) -> c_int;
diff --git a/src/libstd/sys_common/gnu/libbacktrace.rs b/src/libstd/sys_common/gnu/libbacktrace.rs
index d464a13ad1d..0bdbeddb112 100644
--- a/src/libstd/sys_common/gnu/libbacktrace.rs
+++ b/src/libstd/sys_common/gnu/libbacktrace.rs
@@ -39,9 +39,6 @@ pub fn print(w: &mut Write, idx: isize, addr: *mut libc::c_void,
                       msg: *const libc::c_char,
                       errnum: libc::c_int);
     enum backtrace_state {}
-    #[link(name = "backtrace", kind = "static")]
-    #[cfg(all(not(test), not(cargobuild)))]
-    extern {}
 
     extern {
         fn backtrace_create_state(filename: *const libc::c_char,
diff --git a/src/libstd/sys_common/mod.rs b/src/libstd/sys_common/mod.rs
index 634d6258885..d4d3365dc01 100644
--- a/src/libstd/sys_common/mod.rs
+++ b/src/libstd/sys_common/mod.rs
@@ -29,7 +29,7 @@ use sync::Once;
 use sys;
 
 pub mod at_exit_imp;
-#[cfg(any(not(cargobuild), feature = "backtrace"))]
+#[cfg(feature = "backtrace")]
 pub mod backtrace;
 pub mod condvar;
 pub mod io;
@@ -50,7 +50,7 @@ pub use sys::net;
 #[cfg(not(target_os = "redox"))]
 pub mod net;
 
-#[cfg(any(not(cargobuild), feature = "backtrace"))]
+#[cfg(feature = "backtrace")]
 #[cfg(any(all(unix, not(any(target_os = "macos", target_os = "ios", target_os = "emscripten"))),
           all(windows, target_env = "gnu")))]
 pub mod gnu;