Compiling against musl target with openssl-sys dependencies

[tylerjl]

Hey hey! I'm running into issues trying to statically compile against a musl target that has openssl-sys as part of its dependency tree.

I've set the suggested flags and options per the helpful examples, so I'm halfway there and know that cargo is trying to make a static compilation happen:

                  CARGO_BUILD_TARGET = "x86_64-unknown-linux-musl";
                  CARGO_BUILD_RUSTFLAGS = "-C target-feature=+crt-static";

...and my toolchain has musl as an additional target. The issue is that when it comes time to build the openssl-sys crate (which is deeper in my dependency tree as a dependency of another crate), I'm stuck at the following error:

       > error: could not find native static library `ssl`, perhaps an -L flag is missing?
       >
       > error: could not compile `openssl-sys` (lib) due to previous error

I suppose this error makes sense - the crate is trying to find a static library for ssl and not finding it. Per the typical way to do this, I previously had the normal versions of openssl and pkg-config listed as inputs to the derivation, but in an effort to provide the static ssl library, the following doesn't seem to help either:

let
  openssl = pkgs.pkgsMusl.openssl;
  pkg-config = pkgs.pkgsMusl.pkg-config;
in
{
  # ... other crane directives before this
  OPENSSL_STATIC = 1;
  OPENSSL_DIR = openssl;
  OPENSSL_LIB_DIR = openssl;
  OPENSSL_INCLUDE_DIR = openssl;
  buildInputs = [ makeWrapper openssl pkg-config ];
}

Any ideas? I've also tried doing weird stuff like instantiating my crane lib with something like (crane.mkLib pkgs.pkgsMusl) but that doesn't seem to do it either.

This may be something more related to nix and cargo in general, but I'm hoping that there may be something here that I may be overlooking.

[ipetkov]

Hi @tylerjl! Normally I'd expect to see pkg-config (and probably makeWrapper) listed under nativeBuildInputs; maybe that's the issue?