Failing to build: custom build command for openssl-sys fails

[LemmingAvalanche]

I am trying to build this program with cargo build, but I get an error
which seems to be coming from the package openssl-sys, version 0.9.1.

Steps to reproduce

Executed with Rustc version 1.12.0 and Cargo version 0.13.0 in shell
nix-shell --pure -p rustStable.rustc -p rustStable.cargo -p git.

• OS: Ubuntu 14.04

$ git checkout 0.9.1
$ cargo --version
cargo 0.13.0 (built 2016-10-21)
$ rustc --version
rustc 1.12.0
$ RUST_BACKTRACE=1 cargo build
   Compiling openssl-sys v0.9.1
   Compiling num v0.1.36
Build failed, waiting for other jobs to finish...
error: failed to run custom build command for `openssl-sys v0.9.1`
process didn't exit successfully: `<path>/git-and-tools/git-series/repo/git-series/target/debug/build/openssl-sys-76c1fa79ef1208aa/build-script-build` (exit code: 101)
--- stderr
thread 'main' panicked at '

Could not find directory of OpenSSL installation, and this `-sys` crate cannot
proceed without this knowledge. If OpenSSL is installed and this crate had
trouble finding it,  you can set the `OPENSSL_DIR` environment variable for the
compilation process.

If you're in a situation where you think the directory *should* be found
automatically, please open a bug at https://github.com/sfackler/rust-openssl
and include information about your system as well as this message.

    $HOST = x86_64-unknown-linux-gnu
    $TARGET = x86_64-unknown-linux-gnu
    openssl-sys = 0.9.1


It looks like you're compiling on Linux and also targeting Linux. Currently this
requires the `pkg-config` utility to find OpenSSL but unfortunately `pkg-config`
could not be found. If you have OpenSSL installed you can likely fix this by
installing `pkg-config`.

', <home>/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.9.1/build.rs:142
stack backtrace:
   1:     0x563b41d65f0b - std::sys::backtrace::tracing::imp::write::h00e948915d1e4c72
   2:     0x563b41d6cddf - std::panicking::default_hook::_{{closure}}::h7b8a142818383fb8
   3:     0x563b41d6c025 - std::panicking::default_hook::h41cf296f654245d7
   4:     0x563b41d6c6e5 - std::panicking::rust_panic_with_hook::h4cbd7ca63ce1aee9
   5:     0x563b41d28d76 - std::panicking::begin_panic::h93672d0313d5e8e9
                        at /tmp/nix-build-rustc-1.12.0.drv-0/rust-3191fba/src/libstd/panicking.rs:384
   6:     0x563b41d416fb - build_script_build::find_openssl_dir::hb68e52b7bbb3a4dd
                        at <home>/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.9.1/build.rs:3
   7:     0x563b41d43688 - build_script_build::main::_{{closure}}::h3e9f4699862f6d52
                        at <home>/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.9.1/build.rs:15
   8:     0x563b41d23d80 - _<core..option..Option<T>>::unwrap_or_else::heb656dab87effcd3
                        at /tmp/nix-build-rustc-1.12.0.drv-0/rust-3191fba/src/libcore/option.rs:361
   9:     0x563b41d400e9 - build_script_build::main::h73ab0570d224c5dd
                        at <home>/.cargo/registry/src/github.com-1ecc6299db9ec823/openssl-sys-0.9.1/build.rs:14
  10:     0x563b41d72c76 - __rust_maybe_catch_panic
  11:     0x563b41d6ba39 - std::rt::lang_start::h53bf99b0829cc03c
  12:     0x563b41d447a3 - main
  13:     0x7fc3caf3c2df - __libc_start_main
  14:     0x563b41d20769 - _start
                        at ../sysdeps/x86_64/start.S:120
  15:                0x0 - <unknown>

[joshtriplett]

@LemmingAvalanche Do you have pkg-config installed, as well as a -dev package for libssl?

[LemmingAvalanche]

@LemmingAvalanche Do you have pkg-config installed, as well as a -dev
package for libssl?

Good question. I did have pkg-config(1) installed but apparently not
libssl dev.

The thing is that I used the --pure flag to the nix-shell command,
which makes it so that most things are not included on PATH in order
to get more reproducible behaviour. But I was able to make Git-series
build successfully by removing that flag and installing libssl-dev
through APT (my OS package manager).

So running this:

sudo apt-get install libssl-dev
nix-shell -p rustStable.rustc -p rustStable.cargo -p git

Gave me a shell in which I could run RUST_BACKTRACE=1 cargo build with
success.

Closing since now it seems I just need to figure out how to find the
right packages in Nix in order to get this to work as I want (in a
pure way).

⁂

I’ve been unsuccesful in finding the right packages to use from Nix.
I’ve tried the packages libressl, openssl, and pkgconfig, but both
of these Nix shells weren’t good enough:

nix-shell --pure -p rustStable.rustc -p rustStable.cargo -p git -p openssl -p pkgconfig

nix-shell -p rustStable.rustc -p rustStable.cargo -p git -p libressl -p pkgconfig

[LemmingAvalanche]

It turns out that Git-series has been added to Nixpkgs recently:
NixOS/nixpkgs/pull/25666.