Add m-esr52 at 52.6.0

1 files changed, 898 insertions, 0 deletions

diff --git a/third_party/rust/gcc/src/lib.rs b/third_party/rust/gcc/src/lib.rs
new file mode 100644
index 000000000..ea2cc9b86
--- /dev/null
+++ b/third_party/rust/gcc/src/lib.rs
@@ -0,0 +1,898 @@
+//! A library for build scripts to compile custom C code
+//!
+//! This library is intended to be used as a `build-dependencies` entry in
+//! `Cargo.toml`:
+//!
+//! ```toml
+//! [build-dependencies]
+//! gcc = "0.3"
+//! ```
+//!
+//! The purpose of this crate is to provide the utility functions necessary to
+//! compile C code into a static archive which is then linked into a Rust crate.
+//! The top-level `compile_library` function serves as a convenience and more
+//! advanced configuration is available through the `Config` builder.
+//!
+//! This crate will automatically detect situations such as cross compilation or
+//! other environment variables set by Cargo and will build code appropriately.
+//!
+//! # Examples
+//!
+//! Use the default configuration:
+//!
+//! ```no_run
+//! extern crate gcc;
+//!
+//! fn main() {
+//!     gcc::compile_library("libfoo.a", &["src/foo.c"]);
+//! }
+//! ```
+//!
+//! Use more advanced configuration:
+//!
+//! ```no_run
+//! extern crate gcc;
+//!
+//! fn main() {
+//!     gcc::Config::new()
+//!                 .file("src/foo.c")
+//!                 .define("FOO", Some("bar"))
+//!                 .include("src")
+//!                 .compile("libfoo.a");
+//! }
+//! ```
+
+#![doc(html_root_url = "http://alexcrichton.com/gcc-rs")]
+#![cfg_attr(test, deny(warnings))]
+#![deny(missing_docs)]
+
+#[cfg(feature = "parallel")]
+extern crate rayon;
+
+use std::env;
+use std::ffi::{OsString, OsStr};
+use std::fs;
+use std::io;
+use std::path::{PathBuf, Path};
+use std::process::{Command, Stdio};
+use std::io::{BufReader, BufRead, Write};
+
+#[cfg(windows)]
+mod registry;
+pub mod windows_registry;
+
+/// Extra configuration to pass to gcc.
+pub struct Config {
+    include_directories: Vec<PathBuf>,
+    definitions: Vec<(String, Option<String>)>,
+    objects: Vec<PathBuf>,
+    flags: Vec<String>,
+    files: Vec<PathBuf>,
+    cpp: bool,
+    cpp_link_stdlib: Option<Option<String>>,
+    cpp_set_stdlib: Option<String>,
+    target: Option<String>,
+    host: Option<String>,
+    out_dir: Option<PathBuf>,
+    opt_level: Option<u32>,
+    debug: Option<bool>,
+    env: Vec<(OsString, OsString)>,
+    compiler: Option<PathBuf>,
+    archiver: Option<PathBuf>,
+    cargo_metadata: bool,
+    pic: Option<bool>,
+}
+
+/// Configuration used to represent an invocation of a C compiler.
+///
+/// This can be used to figure out what compiler is in use, what the arguments
+/// to it are, and what the environment variables look like for the compiler.
+/// This can be used to further configure other build systems (e.g. forward
+/// along CC and/or CFLAGS) or the `to_command` method can be used to run the
+/// compiler itself.
+pub struct Tool {
+    path: PathBuf,
+    args: Vec<OsString>,
+    env: Vec<(OsString, OsString)>,
+}
+
+/// Compile a library from the given set of input C files.
+///
+/// This will simply compile all files into object files and then assemble them
+/// into the output. This will read the standard environment variables to detect
+/// cross compilations and such.
+///
+/// This function will also print all metadata on standard output for Cargo.
+///
+/// # Example
+///
+/// ```no_run
+/// gcc::compile_library("libfoo.a", &["foo.c", "bar.c"]);
+/// ```
+pub fn compile_library(output: &str, files: &[&str]) {
+    let mut c = Config::new();
+    for f in files.iter() {
+        c.file(*f);
+    }
+    c.compile(output)
+}
+
+impl Config {
+    /// Construct a new instance of a blank set of configuration.
+    ///
+    /// This builder is finished with the `compile` function.
+    pub fn new() -> Config {
+        Config {
+            include_directories: Vec::new(),
+            definitions: Vec::new(),
+            objects: Vec::new(),
+            flags: Vec::new(),
+            files: Vec::new(),
+            cpp: false,
+            cpp_link_stdlib: None,
+            cpp_set_stdlib: None,
+            target: None,
+            host: None,
+            out_dir: None,
+            opt_level: None,
+            debug: None,
+            env: Vec::new(),
+            compiler: None,
+            archiver: None,
+            cargo_metadata: true,
+            pic: None,
+        }
+    }
+
+    /// Add a directory to the `-I` or include path for headers
+    pub fn include<P: AsRef<Path>>(&mut self, dir: P) -> &mut Config {
+        self.include_directories.push(dir.as_ref().to_path_buf());
+        self
+    }
+
+    /// Specify a `-D` variable with an optional value.
+    pub fn define(&mut self, var: &str, val: Option<&str>) -> &mut Config {
+        self.definitions.push((var.to_string(), val.map(|s| s.to_string())));
+        self
+    }
+
+    /// Add an arbitrary object file to link in
+    pub fn object<P: AsRef<Path>>(&mut self, obj: P) -> &mut Config {
+        self.objects.push(obj.as_ref().to_path_buf());
+        self
+    }
+
+    /// Add an arbitrary flag to the invocation of the compiler
+    pub fn flag(&mut self, flag: &str) -> &mut Config {
+        self.flags.push(flag.to_string());
+        self
+    }
+
+    /// Add a file which will be compiled
+    pub fn file<P: AsRef<Path>>(&mut self, p: P) -> &mut Config {
+        self.files.push(p.as_ref().to_path_buf());
+        self
+    }
+
+    /// Set C++ support.
+    ///
+    /// The other `cpp_*` options will only become active if this is set to
+    /// `true`.
+    pub fn cpp(&mut self, cpp: bool) -> &mut Config {
+        self.cpp = cpp;
+        self
+    }
+
+    /// Set the standard library to link against when compiling with C++
+    /// support.
+    ///
+    /// The default value of this property depends on the current target: On
+    /// OS X `Some("c++")` is used, when compiling for a Visual Studio based
+    /// target `None` is used and for other targets `Some("stdc++")` is used.
+    ///
+    /// A value of `None` indicates that no automatic linking should happen,
+    /// otherwise cargo will link against the specified library.
+    ///
+    /// The given library name must not contain the `lib` prefix.
+    pub fn cpp_link_stdlib(&mut self, cpp_link_stdlib: Option<&str>)
+                           -> &mut Config {
+        self.cpp_link_stdlib = Some(cpp_link_stdlib.map(|s| s.into()));
+        self
+    }
+
+    /// Force the C++ compiler to use the specified standard library.
+    ///
+    /// Setting this option will automatically set `cpp_link_stdlib` to the same
+    /// value.
+    ///
+    /// The default value of this option is always `None`.
+    ///
+    /// This option has no effect when compiling for a Visual Studio based
+    /// target.
+    ///
+    /// This option sets the `-stdlib` flag, which is only supported by some
+    /// compilers (clang, icc) but not by others (gcc). The library will not
+    /// detect which compiler is used, as such it is the responsibility of the
+    /// caller to ensure that this option is only used in conjuction with a
+    /// compiler which supports the `-stdlib` flag.
+    ///
+    /// A value of `None` indicates that no specific C++ standard library should
+    /// be used, otherwise `-stdlib` is added to the compile invocation.
+    ///
+    /// The given library name must not contain the `lib` prefix.
+    pub fn cpp_set_stdlib(&mut self, cpp_set_stdlib: Option<&str>)
+                          -> &mut Config {
+        self.cpp_set_stdlib = cpp_set_stdlib.map(|s| s.into());
+        self.cpp_link_stdlib(cpp_set_stdlib);
+        self
+    }
+
+    /// Configures the target this configuration will be compiling for.
+    ///
+    /// This option is automatically scraped from the `TARGET` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn target(&mut self, target: &str) -> &mut Config {
+        self.target = Some(target.to_string());
+        self
+    }
+
+    /// Configures the host assumed by this configuration.
+    ///
+    /// This option is automatically scraped from the `HOST` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn host(&mut self, host: &str) -> &mut Config {
+        self.host = Some(host.to_string());
+        self
+    }
+
+    /// Configures the optimization level of the generated object files.
+    ///
+    /// This option is automatically scraped from the `OPT_LEVEL` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn opt_level(&mut self, opt_level: u32) -> &mut Config {
+        self.opt_level = Some(opt_level);
+        self
+    }
+
+    /// Configures whether the compiler will emit debug information when
+    /// generating object files.
+    ///
+    /// This option is automatically scraped from the `PROFILE` environment
+    /// variable by build scripts (only enabled when the profile is "debug"), so
+    /// it's not required to call this function.
+    pub fn debug(&mut self, debug: bool) -> &mut Config {
+        self.debug = Some(debug);
+        self
+    }
+
+    /// Configures the output directory where all object files and static
+    /// libraries will be located.
+    ///
+    /// This option is automatically scraped from the `OUT_DIR` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn out_dir<P: AsRef<Path>>(&mut self, out_dir: P) -> &mut Config {
+        self.out_dir = Some(out_dir.as_ref().to_owned());
+        self
+    }
+
+    /// Configures the compiler to be used to produce output.
+    ///
+    /// This option is automatically determined from the target platform or a
+    /// number of environment variables, so it's not required to call this
+    /// function.
+    pub fn compiler<P: AsRef<Path>>(&mut self, compiler: P) -> &mut Config {
+        self.compiler = Some(compiler.as_ref().to_owned());
+        self
+    }
+
+    /// Configures the tool used to assemble archives.
+    ///
+    /// This option is automatically determined from the target platform or a
+    /// number of environment variables, so it's not required to call this
+    /// function.
+    pub fn archiver<P: AsRef<Path>>(&mut self, archiver: P) -> &mut Config {
+        self.archiver = Some(archiver.as_ref().to_owned());
+        self
+    }
+    /// Define whether metadata should be emitted for cargo allowing it to
+    /// automatically link the binary. Defaults to `true`.
+    pub fn cargo_metadata(&mut self, cargo_metadata: bool) -> &mut Config {
+        self.cargo_metadata = cargo_metadata;
+        self
+    }
+
+    /// Configures whether the compiler will emit position independent code.
+    ///
+    /// This option defaults to `false` for `i686` and `windows-gnu` targets and to `true` for all
+    /// other targets.
+    pub fn pic(&mut self, pic: bool) -> &mut Config {
+        self.pic = Some(pic);
+        self
+    }
+
+
+    #[doc(hidden)]
+    pub fn __set_env<A, B>(&mut self, a: A, b: B) -> &mut Config
+        where A: AsRef<OsStr>, B: AsRef<OsStr>
+    {
+        self.env.push((a.as_ref().to_owned(), b.as_ref().to_owned()));
+        self
+    }
+
+    /// Run the compiler, generating the file `output`
+    ///
+    /// The name `output` must begin with `lib` and end with `.a`
+    pub fn compile(&self, output: &str) {
+        assert!(output.starts_with("lib"));
+        assert!(output.ends_with(".a"));
+        let lib_name = &output[3..output.len() - 2];
+        let dst = self.get_out_dir();
+
+        let mut objects = Vec::new();
+        let mut src_dst = Vec::new();
+        for file in self.files.iter() {
+            let obj = dst.join(file).with_extension("o");
+            let obj = if !obj.starts_with(&dst) {
+                dst.join(obj.file_name().unwrap())
+            } else {
+                obj
+            };
+            fs::create_dir_all(&obj.parent().unwrap()).unwrap();
+            src_dst.push((file.to_path_buf(), obj.clone()));
+            objects.push(obj);
+        }
+        self.compile_objects(&src_dst);
+        self.assemble(lib_name, &dst.join(output), &objects);
+
+        self.print(&format!("cargo:rustc-link-lib=static={}",
+                            &output[3..output.len() - 2]));
+        self.print(&format!("cargo:rustc-link-search=native={}", dst.display()));
+
+        // Add specific C++ libraries, if enabled.
+        if self.cpp {
+            if let Some(stdlib) = self.get_cpp_link_stdlib() {
+                self.print(&format!("cargo:rustc-link-lib={}", stdlib));
+            }
+        }
+    }
+
+    #[cfg(feature = "parallel")]
+    fn compile_objects(&self, objs: &[(PathBuf, PathBuf)]) {
+        use self::rayon::prelude::*;
+
+        let mut cfg = rayon::Configuration::new();
+        if let Ok(amt) = env::var("NUM_JOBS") {
+            if let Ok(amt) = amt.parse() {
+                cfg = cfg.set_num_threads(amt);
+            }
+        }
+        drop(rayon::initialize(cfg));
+
+        objs.par_iter().weight_max().for_each(|&(ref src, ref dst)| {
+            self.compile_object(src, dst)
+        })
+    }
+
+    #[cfg(not(feature = "parallel"))]
+    fn compile_objects(&self, objs: &[(PathBuf, PathBuf)]) {
+        for &(ref src, ref dst) in objs {
+            self.compile_object(src, dst);
+        }
+    }
+
+    fn compile_object(&self, file: &Path, dst: &Path) {
+        let is_asm = file.extension().and_then(|s| s.to_str()) == Some("asm");
+        let msvc = self.get_target().contains("msvc");
+        let (mut cmd, name) = if msvc && is_asm {
+            self.msvc_macro_assembler()
+        } else {
+            let compiler = self.get_compiler();
+            let mut cmd = compiler.to_command();
+            for &(ref a, ref b) in self.env.iter() {
+                cmd.env(a, b);
+            }
+            (cmd, compiler.path.file_name().unwrap()
+                          .to_string_lossy().into_owned())
+        };
+        if msvc && is_asm {
+            cmd.arg("/Fo").arg(dst);
+        } else if msvc {
+            let mut s = OsString::from("/Fo");
+            s.push(&dst);
+            cmd.arg(s);
+        } else {
+            cmd.arg("-o").arg(&dst);
+        }
+        cmd.arg(if msvc {"/c"} else {"-c"});
+        cmd.arg(file);
+
+        run(&mut cmd, &name);
+    }
+
+    /// Get the compiler that's in use for this configuration.
+    ///
+    /// This function will return a `Tool` which represents the culmination
+    /// of this configuration at a snapshot in time. The returned compiler can
+    /// be inspected (e.g. the path, arguments, environment) to forward along to
+    /// other tools, or the `to_command` method can be used to invoke the
+    /// compiler itself.
+    ///
+    /// This method will take into account all configuration such as debug
+    /// information, optimization level, include directories, defines, etc.
+    /// Additionally, the compiler binary in use follows the standard
+    /// conventions for this path, e.g. looking at the explicitly set compiler,
+    /// environment variables (a number of which are inspected here), and then
+    /// falling back to the default configuration.
+    pub fn get_compiler(&self) -> Tool {
+        let opt_level = self.get_opt_level();
+        let debug = self.get_debug();
+        let target = self.get_target();
+        let msvc = target.contains("msvc");
+        self.print(&format!("debug={} opt-level={}", debug, opt_level));
+
+        let mut cmd = self.get_base_compiler();
+        let nvcc = cmd.path.to_str()
+            .map(|path| path.contains("nvcc"))
+            .unwrap_or(false);
+
+        if msvc {
+            cmd.args.push("/nologo".into());
+            cmd.args.push("/MD".into()); // link against msvcrt.dll for now
+            if opt_level != 0 {
+                cmd.args.push("/O2".into());
+            }
+            if target.contains("i686") {
+                cmd.args.push("/SAFESEH".into());
+            } else if target.contains("i586") {
+                cmd.args.push("/SAFESEH".into());
+                cmd.args.push("/ARCH:IA32".into());
+            }
+        } else if nvcc {
+            cmd.args.push(format!("-O{}", opt_level).into());
+        } else {
+            cmd.args.push(format!("-O{}", opt_level).into());
+            cmd.args.push("-ffunction-sections".into());
+            cmd.args.push("-fdata-sections".into());
+        }
+        for arg in self.envflags(if self.cpp {"CXXFLAGS"} else {"CFLAGS"}) {
+            cmd.args.push(arg.into());
+        }
+
+        if debug {
+            cmd.args.push(if msvc {"/Z7"} else {"-g"}.into());
+        }
+
+        if target.contains("-ios") {
+            self.ios_flags(&mut cmd);
+        } else if !msvc {
+            if target.contains("i686") || target.contains("i586") {
+                cmd.args.push("-m32".into());
+            } else if target.contains("x86_64") || target.contains("powerpc64") {
+                cmd.args.push("-m64".into());
+            }
+
+            if !nvcc && self.pic.unwrap_or(!target.contains("i686") && !target.contains("windows-gnu")) {
+                cmd.args.push("-fPIC".into());
+            } else if nvcc && self.pic.unwrap_or(false) {
+                cmd.args.push("-Xcompiler".into());
+                cmd.args.push("\'-fPIC\'".into());
+            }
+            if target.contains("musl") {
+                cmd.args.push("-static".into());
+            }
+
+            if target.starts_with("armv7-unknown-linux-") {
+                cmd.args.push("-march=armv7-a".into());
+            }
+            if target.starts_with("arm-unknown-linux-") {
+                cmd.args.push("-march=armv6".into());
+                cmd.args.push("-marm".into());
+            }
+            if target.starts_with("i586-unknown-linux-") {
+                cmd.args.push("-march=pentium".into());
+            }
+            if target.starts_with("i686-unknown-linux-") {
+                cmd.args.push("-march=i686".into());
+            }
+        }
+
+        if self.cpp && !msvc {
+            if let Some(ref stdlib) = self.cpp_set_stdlib {
+                cmd.args.push(format!("-stdlib=lib{}", stdlib).into());
+            }
+        }
+
+        for directory in self.include_directories.iter() {
+            cmd.args.push(if msvc {"/I"} else {"-I"}.into());
+            cmd.args.push(directory.into());
+        }
+
+        for flag in self.flags.iter() {
+            cmd.args.push(flag.into());
+        }
+
+        for &(ref key, ref value) in self.definitions.iter() {
+            let lead = if msvc {"/"} else {"-"};
+            if let &Some(ref value) = value {
+                cmd.args.push(format!("{}D{}={}", lead, key, value).into());
+            } else {
+                cmd.args.push(format!("{}D{}", lead, key).into());
+            }
+        }
+        cmd
+    }
+
+    fn msvc_macro_assembler(&self) -> (Command, String) {
+        let target = self.get_target();
+        let tool = if target.contains("x86_64") {"ml64.exe"} else {"ml.exe"};
+        let mut cmd = windows_registry::find(&target, tool).unwrap_or_else(|| {
+            self.cmd(tool)
+        });
+        for directory in self.include_directories.iter() {
+            cmd.arg("/I").arg(directory);
+        }
+        for &(ref key, ref value) in self.definitions.iter() {
+            if let &Some(ref value) = value {
+                cmd.arg(&format!("/D{}={}", key, value));
+            } else {
+                cmd.arg(&format!("/D{}", key));
+            }
+        }
+
+        if target.contains("i686") || target.contains("i586") {
+            cmd.arg("/safeseh");
+        }
+        for flag in self.flags.iter() {
+            cmd.arg(flag);
+        }
+
+        (cmd, tool.to_string())
+    }
+
+    fn assemble(&self, lib_name: &str, dst: &Path, objects: &[PathBuf]) {
+        // Delete the destination if it exists as the `ar` tool at least on Unix
+        // appends to it, which we don't want.
+        let _ = fs::remove_file(&dst);
+
+        let target = self.get_target();
+        if target.contains("msvc") {
+            let mut cmd = match self.archiver {
+                Some(ref s) => self.cmd(s),
+                None => windows_registry::find(&target, "lib.exe")
+                                         .unwrap_or(self.cmd("lib.exe")),
+            };
+            let mut out = OsString::from("/OUT:");
+            out.push(dst);
+            run(cmd.arg(out).arg("/nologo")
+                   .args(objects)
+                   .args(&self.objects), "lib.exe");
+
+            // The Rust compiler will look for libfoo.a and foo.lib, but the
+            // MSVC linker will also be passed foo.lib, so be sure that both
+            // exist for now.
+            let lib_dst = dst.with_file_name(format!("{}.lib", lib_name));
+            let _ = fs::remove_file(&lib_dst);
+            fs::hard_link(&dst, &lib_dst).or_else(|_| {
+                //if hard-link fails, just copy (ignoring the number of bytes written)
+                fs::copy(&dst, &lib_dst).map(|_| ())
+            }).ok().expect("Copying from {:?} to {:?} failed.");;
+        } else {
+            let ar = self.get_ar();
+            let cmd = ar.file_name().unwrap().to_string_lossy();
+            run(self.cmd(&ar).arg("crus")
+                                 .arg(dst)
+                                 .args(objects)
+                                 .args(&self.objects), &cmd);
+        }
+    }
+
+    fn ios_flags(&self, cmd: &mut Tool) {
+        enum ArchSpec {
+            Device(&'static str),
+            Simulator(&'static str),
+        }
+
+        let target = self.get_target();
+        let arch = target.split('-').nth(0).unwrap();
+        let arch = match arch {
+            "arm" | "armv7" | "thumbv7" => ArchSpec::Device("armv7"),
+            "armv7s" | "thumbv7s" => ArchSpec::Device("armv7s"),
+            "arm64" | "aarch64" => ArchSpec::Device("arm64"),
+            "i386" | "i686" => ArchSpec::Simulator("-m32"),
+            "x86_64" => ArchSpec::Simulator("-m64"),
+            _ => fail("Unknown arch for iOS target")
+        };
+
+        let sdk = match arch {
+            ArchSpec::Device(arch) => {
+                cmd.args.push("-arch".into());
+                cmd.args.push(arch.into());
+                cmd.args.push("-miphoneos-version-min=7.0".into());
+                "iphoneos"
+            },
+            ArchSpec::Simulator(arch) => {
+                cmd.args.push(arch.into());
+                cmd.args.push("-mios-simulator-version-min=7.0".into());
+                "iphonesimulator"
+            }
+        };
+
+        self.print(&format!("Detecting iOS SDK path for {}", sdk));
+        let sdk_path = self.cmd("xcrun")
+            .arg("--show-sdk-path")
+            .arg("--sdk")
+            .arg(sdk)
+            .stderr(Stdio::inherit())
+            .output()
+            .unwrap()
+            .stdout;
+
+        let sdk_path = String::from_utf8(sdk_path).unwrap();
+
+        cmd.args.push("-isysroot".into());
+        cmd.args.push(sdk_path.trim().into());
+    }
+
+    fn cmd<P: AsRef<OsStr>>(&self, prog: P) -> Command {
+        let mut cmd = Command::new(prog);
+        for &(ref a, ref b) in self.env.iter() {
+            cmd.env(a, b);
+        }
+        return cmd
+    }
+
+    fn get_base_compiler(&self) -> Tool {
+        if let Some(ref c) = self.compiler {
+            return Tool::new(c.clone())
+        }
+        let host = self.get_host();
+        let target = self.get_target();
+        let (env, msvc, gnu, default) = if self.cpp {
+            ("CXX", "cl.exe", "g++", "c++")
+        } else {
+            ("CC", "cl.exe", "gcc", "cc")
+        };
+        self.env_tool(env).map(|(tool, args)| {
+            let mut t = Tool::new(PathBuf::from(tool));
+            for arg in args {
+                t.args.push(arg.into());
+            }
+            return t
+        }).or_else(|| {
+            windows_registry::find_tool(&target, "cl.exe")
+        }).unwrap_or_else(|| {
+            let compiler = if host.contains("windows") &&
+                              target.contains("windows") {
+                if target.contains("msvc") {
+                    msvc.to_string()
+                } else {
+                    format!("{}.exe", gnu)
+                }
+            } else if target.contains("android") {
+                format!("{}-{}", target, gnu)
+            } else if self.get_host() != target {
+                let prefix = match &target[..] {
+                    "aarch64-unknown-linux-gnu" => Some("aarch64-linux-gnu"),
+                    "arm-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
+                    "arm-unknown-linux-gnueabihf"  => Some("arm-linux-gnueabihf"),
+                    "armv7-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
+                    "arm-unknown-linux-musleabi" => Some("arm-linux-musleabi"),
+                    "arm-unknown-linux-musleabihf"  => Some("arm-linux-musleabihf"),
+                    "armv7-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
+                    "powerpc-unknown-linux-gnu" => Some("powerpc-linux-gnu"),
+                    "powerpc64-unknown-linux-gnu" => Some("powerpc-linux-gnu"),
+                    "powerpc64le-unknown-linux-gnu" => Some("powerpc64le-linux-gnu"),
+                    "mips-unknown-linux-gnu" => Some("mips-linux-gnu"),
+                    "mipsel-unknown-linux-gnu" => Some("mipsel-linux-gnu"),
+                    "i686-pc-windows-gnu" => Some("i686-w64-mingw32"),
+                    "x86_64-pc-windows-gnu" => Some("x86_64-w64-mingw32"),
+                    "x86_64-unknown-linux-musl" => Some("musl"),
+                    "x86_64-rumprun-netbsd" => Some("x86_64-rumprun-netbsd"),
+                    _ => None,
+                };
+                match prefix {
+                    Some(prefix) => format!("{}-{}", prefix, gnu),
+                    None => default.to_string(),
+                }
+            } else {
+                default.to_string()
+            };
+            Tool::new(PathBuf::from(compiler))
+        })
+    }
+
+    fn get_var(&self, var_base: &str) -> Result<String, String> {
+        let target = self.get_target();
+        let host = self.get_host();
+        let kind = if host == target {"HOST"} else {"TARGET"};
+        let target_u = target.replace("-", "_");
+        let res = self.getenv(&format!("{}_{}", var_base, target))
+            .or_else(|| self.getenv(&format!("{}_{}", var_base, target_u)))
+            .or_else(|| self.getenv(&format!("{}_{}", kind, var_base)))
+            .or_else(|| self.getenv(var_base));
+
+        match res {
+            Some(res) => Ok(res),
+            None => Err("could not get environment variable".to_string()),
+        }
+    }
+
+    fn envflags(&self, name: &str) -> Vec<String> {
+        self.get_var(name).unwrap_or(String::new())
+            .split(|c: char| c.is_whitespace()).filter(|s| !s.is_empty())
+            .map(|s| s.to_string())
+            .collect()
+    }
+
+    fn env_tool(&self, name: &str) -> Option<(String, Vec<String>)> {
+        self.get_var(name).ok().map(|tool| {
+            let whitelist = ["ccache", "distcc"];
+            for t in whitelist.iter() {
+                if tool.starts_with(t) && tool[t.len()..].starts_with(" ") {
+                    return (t.to_string(),
+                            vec![tool[t.len()..].trim_left().to_string()])
+                }
+            }
+            (tool, Vec::new())
+        })
+    }
+
+    /// Returns the default C++ standard library for the current target: `libc++`
+    /// for OS X and `libstdc++` for anything else.
+    fn get_cpp_link_stdlib(&self) -> Option<String> {
+        self.cpp_link_stdlib.clone().unwrap_or_else(|| {
+            let target = self.get_target();
+            if target.contains("msvc") {
+                None
+            } else if target.contains("darwin") {
+                Some("c++".to_string())
+            } else {
+                Some("stdc++".to_string())
+            }
+        })
+    }
+
+    fn get_ar(&self) -> PathBuf {
+        self.archiver.clone().or_else(|| {
+            self.get_var("AR").map(PathBuf::from).ok()
+        }).unwrap_or_else(|| {
+            if self.get_target().contains("android") {
+                PathBuf::from(format!("{}-ar", self.get_target()))
+            } else {
+                PathBuf::from("ar")
+            }
+        })
+    }
+
+    fn get_target(&self) -> String {
+        self.target.clone().unwrap_or_else(|| self.getenv_unwrap("TARGET"))
+    }
+
+    fn get_host(&self) -> String {
+        self.host.clone().unwrap_or_else(|| self.getenv_unwrap("HOST"))
+    }
+
+    fn get_opt_level(&self) -> u32 {
+        self.opt_level.unwrap_or_else(|| {
+            self.getenv_unwrap("OPT_LEVEL").parse().unwrap()
+        })
+    }
+
+    fn get_debug(&self) -> bool {
+        self.debug.unwrap_or_else(|| self.getenv_unwrap("PROFILE") == "debug")
+    }
+
+    fn get_out_dir(&self) -> PathBuf {
+        self.out_dir.clone().unwrap_or_else(|| {
+            env::var_os("OUT_DIR").map(PathBuf::from).unwrap()
+        })
+    }
+
+    fn getenv(&self, v: &str) -> Option<String> {
+        let r = env::var(v).ok();
+        self.print(&format!("{} = {:?}", v, r));
+        r
+    }
+
+    fn getenv_unwrap(&self, v: &str) -> String {
+        match self.getenv(v) {
+            Some(s) => s,
+            None => fail(&format!("environment variable `{}` not defined", v)),
+        }
+    }
+
+    fn print(&self, s: &str) {
+        if self.cargo_metadata {
+            println!("{}", s);
+        }
+    }
+}
+
+impl Tool {
+    fn new(path: PathBuf) -> Tool {
+        Tool {
+            path: path,
+            args: Vec::new(),
+            env: Vec::new(),
+        }
+    }
+
+    /// Converts this compiler into a `Command` that's ready to be run.
+    ///
+    /// This is useful for when the compiler needs to be executed and the
+    /// command returned will already have the initial arguments and environment
+    /// variables configured.
+    pub fn to_command(&self) -> Command {
+        let mut cmd = Command::new(&self.path);
+        cmd.args(&self.args);
+        for &(ref k, ref v) in self.env.iter() {
+            cmd.env(k, v);
+        }
+        return cmd
+    }
+
+    /// Returns the path for this compiler.
+    ///
+    /// Note that this may not be a path to a file on the filesystem, e.g. "cc",
+    /// but rather something which will be resolved when a process is spawned.
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
+    /// Returns the default set of arguments to the compiler needed to produce
+    /// executables for the target this compiler generates.
+    pub fn args(&self) -> &[OsString] {
+        &self.args
+    }
+
+    /// Returns the set of environment variables needed for this compiler to
+    /// operate.
+    ///
+    /// This is typically only used for MSVC compilers currently.
+    pub fn env(&self) -> &[(OsString, OsString)] {
+        &self.env
+    }
+}
+
+fn run(cmd: &mut Command, program: &str) {
+    println!("running: {:?}", cmd);
+    // Capture the standard error coming from these programs, and write it out
+    // with cargo:warning= prefixes. Note that this is a bit wonky to avoid
+    // requiring the output to be UTF-8, we instead just ship bytes from one
+    // location to another.
+    let spawn_result = match cmd.stderr(Stdio::piped()).spawn() {
+        Ok(mut child) => {
+            let stderr = BufReader::new(child.stderr.take().unwrap());
+            for line in stderr.split(b'\n').filter_map(|l| l.ok()) {
+                print!("cargo:warning=");
+                std::io::stdout().write_all(&line).unwrap();
+                println!("");
+            }
+            child.wait()
+        }
+        Err(e) => Err(e),
+    };
+    let status = match spawn_result {
+        Ok(status) => status,
+        Err(ref e) if e.kind() == io::ErrorKind::NotFound => {
+            let extra = if cfg!(windows) {
+                " (see https://github.com/alexcrichton/gcc-rs#compile-time-requirements \
+                   for help)"
+            } else {
+                ""
+            };
+            fail(&format!("failed to execute command: {}\nIs `{}` \
+                           not installed?{}", e, program, extra));
+        }
+        Err(e) => fail(&format!("failed to execute command: {}", e)),
+    };
+    println!("{:?}", status);
+    if !status.success() {
+        fail(&format!("command did not execute successfully, got: {}", status));
+    }
+}
+
+fn fail(s: &str) -> ! {
+    println!("\n\n{}\n\n", s);
+    panic!()
+}