bootstrap: Add build scripts for crates

This commits adds build scripts to the necessary Rust crates for all the native
dependencies. This is currently a duplication of the support found in mk/rt.mk
and is my best effort at representing the logic twice, but there may be some
unfortunate-and-inevitable divergence.

As a summary:

* alloc_jemalloc - build script to compile jemallocal
* flate - build script to compile miniz.c
* rustc_llvm - build script to run llvm-config and learn about how to link it.
  Note that this crucially (and will not ever) compile LLVM as that would take
  far too long.
* rustdoc - build script to compile hoedown
* std - script to determine lots of libraries/linkages as well as compile
  libbacktrace

src/libstd/build.rs

@@ -0,0 +1,110 @@
+// Copyright 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.
+
+extern crate gcc;
+extern crate build_helper;
+
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+use std::process::Command;
+
+use build_helper::run;
+
+fn main() {
+    let target = env::var("TARGET").unwrap();
+    let host = env::var("HOST").unwrap();
+    if !target.contains("apple") && !target.contains("msvc") {
+        build_libbacktrace(&host, &target);
+    }
+
+    if target.contains("unknown-linux") {
+        if target.contains("musl") {
+            println!("cargo:rustc-link-lib=static=unwind");
+        } else {
+            println!("cargo:rustc-link-lib=dl");
+            println!("cargo:rustc-link-lib=rt");
+            println!("cargo:rustc-link-lib=pthread");
+            println!("cargo:rustc-link-lib=gcc_s");
+        }
+    } else if target.contains("android") {
+        println!("cargo:rustc-link-lib=dl");
+        println!("cargo:rustc-link-lib=log");
+        println!("cargo:rustc-link-lib=gcc");
+    } else if target.contains("freebsd") {
+        println!("cargo:rustc-link-lib=execinfo");
+        println!("cargo:rustc-link-lib=pthread");
+        println!("cargo:rustc-link-lib=gcc_s");
+    } else if target.contains("dragonfly") || target.contains("bitrig") ||
+              target.contains("netbsd") || target.contains("openbsd") {
+        println!("cargo:rustc-link-lib=pthread");
+
+        if target.contains("rumprun") {
+            println!("cargo:rustc-link-lib=unwind");
+        } else if target.contains("netbsd") || target.contains("openbsd") {
+            println!("cargo:rustc-link-lib=gcc");
+        } else if target.contains("bitrig") {
+            println!("cargo:rustc-link-lib=c++abi");
+        } else if target.contains("dragonfly") {
+            println!("cargo:rustc-link-lib=gcc_pic");
+        }
+    } else if target.contains("apple-darwin") {
+        println!("cargo:rustc-link-lib=System");
+    } else if target.contains("apple-ios") {
+        println!("cargo:rustc-link-lib=System");
+        println!("cargo:rustc-link-lib=objc");
+        println!("cargo:rustc-link-lib=framework=Security");
+        println!("cargo:rustc-link-lib=framework=Foundation");
+    } else if target.contains("windows") {
+        if target.contains("windows-gnu") {
+            println!("cargo:rustc-link-lib=gcc_eh");
+        }
+        println!("cargo:rustc-link-lib=advapi32");
+        println!("cargo:rustc-link-lib=ws2_32");
+        println!("cargo:rustc-link-lib=userenv");
+        println!("cargo:rustc-link-lib=shell32");
+    }
+}
+
+fn build_libbacktrace(host: &str, target: &str) {
+    let src_dir = env::current_dir().unwrap().join("../libbacktrace");
+    let build_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
+
+    println!("cargo:rustc-link-lib=static=backtrace");
+    println!("cargo:rustc-link-search=native={}/.libs", build_dir.display());
+
+    if fs::metadata(&build_dir.join(".libs/libbacktrace.a")).is_ok() {
+        return
+    }
+
+    let compiler = gcc::Config::new().get_compiler();
+    let ar = build_helper::cc2ar(compiler.path(), target);
+    let cflags = compiler.args().iter().map(|s| s.to_str().unwrap())
+                         .collect::<Vec<_>>().join(" ");
+    run(Command::new("sh")
+                .current_dir(&build_dir)
+                .arg(src_dir.join("configure").to_str().unwrap()
+                            .replace("C:\\", "/c/")
+                            .replace("\\", "/"))
+                .arg("--with-pic")
+                .arg("--disable-multilib")
+                .arg("--disable-shared")
+                .arg("--disable-host-shared")
+                .arg(format!("--host={}", build_helper::gnu_target(target)))
+                .arg(format!("--build={}", build_helper::gnu_target(host)))
+                .env("CC", compiler.path())
+                .env("AR", &ar)
+                .env("RANLIB", format!("{} s", ar.display()))
+                .env("CFLAGS", cflags));
+    run(Command::new("make")
+                .current_dir(&build_dir)
+                .arg(format!("INCDIR={}", src_dir.display()))
+                .arg("-j").arg(env::var("NUM_JOBS").unwrap()));
+}