OUT_DIR not set when building doc tests

[chris-morgan]

Cargo.toml:

[package]
name = "foo"
version = "0.0.1"
authors = []
build = "build.rs"

src/lib.rs:

fn it_works() {
    println!("{}", env!("OUT_DIR"));
}

build.rs:

fn main() { }

Now, cargo build works and the first part of cargo test works, but when it gets to the doc tests, it falls apart:

$ cargo test
   Compiling foo v0.0.1 (file:///tmp/foo)
/tmp/foo/src/lib.rs:1:1: 3:2 warning: function is never used: `it_works`, #[warn(dead_code)] on by default
/tmp/foo/src/lib.rs:1 fn it_works() {
/tmp/foo/src/lib.rs:2     println!("{}", env!("OUT_DIR"));
/tmp/foo/src/lib.rs:3 }
     Running target/foo-9c5c49d595bfa18b

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured

   Doc-tests foo
/tmp/foo/src/lib.rs:2:5: 2:37 error: environment variable `OUT_DIR` not defined
/tmp/foo/src/lib.rs:2     println!("{}", env!("OUT_DIR"));
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to previous error
task '<main>' panicked at 'Box<Any>', /home/chris/rust/src/libsyntax/diagnostic.rs:142

This is completely crippling.

I presume the other environment variables aren’t set either, but I haven’t checked.

[alexcrichton]

Fixed in #897