Linking failures with libz and search path

[jetuk]

I am having some trouble linking to highs-sys from my own crate. This is using v1.5.0 and rust v1.67.0 on Fedora 37. I have found two problems:

1. Missing libz requirement.

   = note: /usr/bin/ld: /home/runner/work/pywr-next/pywr-next/target/debug/deps/libhighs_sys-0966d10c628bb43f.rlib(HMPSIO.cpp.o): undefined reference to symbol 'inflateEnd'
          /usr/bin/ld: /lib/x86_64-linux-gnu/libz.so.1: error adding symbols: DSO missing from command line
          collect2: error: ld returned 1 exit status

Full build log is here: https://github.com/pywr/pywr-next/actions/runs/4158414784/jobs/7193618930

I fixed this locally by adding the following to build.rs.

    println!("cargo:rustc-link-lib=dylib=z");

2. Failing to find the static library in the local build directory. For some reason it is added to lib64 and not lib on my system. I had to change build.rs to point to lib64 locally.

    println!("cargo:rustc-link-search=native={}/lib64", dst.display());

I am not at all sure why the tests for highs-sys pass fine with no modifications to build.rs, but I need both of these changes when linking from my crate. What am I doing wrong?

[bluenote-1577]

Issue 2. also appears for me on CentOS 7 with rust v1.67.1 and highs v1.5.0 (but I didn't have issue 1 appear).

Could issue 2 be resolved by simply having both

    println!("cargo:rustc-link-search=native={}/lib64", dst.display());
    println!("cargo:rustc-link-search=native={}/lib", dst.display());

be present, to search both lib and lib64?

[Thell]

I too needed to link libz and println!("cargo:rustc-link-lib=z"); did the job.
Perhaps my simplistic solution is too simplistic and narrow for a pull request #10 but at least there's a test included that will test if it is working or not.

Edit: Just wanted to leave a note and say the this did not work on Windows by itself but works if libz-sys is added as a dep. 👍