build.rs doesn't work with custom target-dir

[bbatha]

Cargo is unable to build openssl-sys if your cargo config sets "target-dir" to an alternate location.

$ cargo build --verbose
   Compiling bitflags v0.6.0
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/bitflags-0.6.0/src/lib.rs --crate-name bitflags --crate-type lib -g -C metadata=01727bf67df6b16b -C extra-filename=-01727bf67df6b16b --out-dir rust-obj/debug/deps --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --cap-lints allow`
   Compiling gcc v0.3.28
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/gcc-0.3.28/src/lib.rs --crate-name gcc --crate-type lib -g -C metadata=2e3f9b8efefd9144 -C extra-filename=-2e3f9b8efefd9144 --out-dir rust-obj/debug/deps --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --cap-lints allow`
   Compiling libc v0.2.11
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/libc-0.2.11/src/lib.rs --crate-name libc --crate-type lib -g --cfg feature=\"use_std\" --cfg feature=\"default\" -C metadata=7f0d63b960234050 -C extra-filename=-7f0d63b960234050 --out-dir rust-obj/debug/deps --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --cap-lints allow`
   Compiling lazy_static v0.2.1
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/lazy_static-0.2.1/src/lib.rs --crate-name lazy_static --crate-type lib -g -C metadata=8c84f489cd3e7d4a -C extra-filename=-8c84f489cd3e7d4a --out-dir rust-obj/debug/deps --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --cap-lints allow`
   Compiling pkg-config v0.3.8
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/pkg-config-0.3.8/src/lib.rs --crate-name pkg_config --crate-type lib -g -C metadata=4db00a0f261b88d6 -C extra-filename=-4db00a0f261b88d6 --out-dir rust-obj/debug/deps --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --cap-lints allow`
   Compiling openssl-sys v0.7.11
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/openssl-sys-0.7.11/build.rs --crate-name build_script_build --crate-type bin -g --out-dir rust-obj/debug/build/openssl-sys-34e294f784d96ad8 --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --extern pkg_config=rust-obj/debug/deps/libpkg_config-4db00a0f261b88d6.rlib --cap-lints allow`
   Compiling openssl-sys-extras v0.7.11
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/openssl-sys-extras-0.7.11/build.rs --crate-name build_script_build --crate-type bin -g --out-dir rust-obj/debug/build/openssl-sys-extras-e1c84960cd35bc93 --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --extern gcc=rust-obj/debug/deps/libgcc-2e3f9b8efefd9144.rlib --cap-lints allow`
   Compiling openssl v0.7.11
     Running `rustc /home/user/bbatha/.multirust/cargo/registry/src/github.jparrowsec.cn-88ac128001ac3a9a/openssl-0.7.11/build.rs --crate-name build_script_build --crate-type bin -g --out-dir rust-obj/debug/build/openssl-5eb24e119ff837c6 --emit=dep-info,link -L dependency=rust-obj/debug/deps -L dependency=rust-obj/debug/deps --extern gcc=rust-obj/debug/deps/libgcc-2e3f9b8efefd9144.rlib --cap-lints allow`
     Running `rust-obj/debug/build/openssl-sys-34e294f784d96ad8/build-script-build`
Build failed, waiting for other jobs to finish...
failed to run custom build command for `openssl-sys v0.7.11`
Could not execute process `rust-obj/debug/build/openssl-sys-34e294f784d96ad8/build-script-build` (never executed)

Caused by:
  No such file or directory (os error 2)

$ cat .cargo/config
[build]
target-dir = "rust-obj"

$ cat Cargo.toml
[package]
name = "test"
version = "0.1.0"

[dependencies]
openssl = "*"

[sfackler]

This sounds like a cargo bug - we don't do anything special with the build script.

[bbatha]

Definitely a cargo bug see rust-lang/cargo#2700