autotools/configure&make support for build.rs

A build dependency to compile a native library that uses autotools or a compatible configure script + make.

It is based on cmake-rs and the API tries to be as similar as possible to it.

For Emscripten targets like "wasm32-unknown-emscripten", configure and make invocations are passed as arguments to emconfigure and emmake respectively as described in the Emscripten docs.

``` toml

Cargo.toml

[build-dependencies] autotools = "0.2" ```

``` rust // build.rs use autotools;

// Build the project in the path foo and installs it in $OUT_DIR let dst = autotools::build("foo");

// Simply link the library without using pkg-config println!("cargo:rustc-link-search=native={}", dst.display()); println!("cargo:rustc-link-lib=static=foo"); ```

``` rust // build.rs use autotools::Config;

let dst = Config::new("foo") .reconf("-ivf") .enable("feature", None) .with("dep", None) .disable("otherfeature", None) .without("otherdep", None) .cflag("-Wall") .build(); ```