# my_repo/build_complex_thing/build

    #!/bin/sh
    set -e

    # The first 2 arguments will be
    ZIG_TRIPLE=$1
    ZIG_OPTIMIZE=$2

    # Use Alpine packages, which get cached in the global Zig cache
    apk add gcc musl-dev make

    # Do whatever. You have access to the whole filesystem.
    # Everything except for /zig-out gets thrown away.
    cd foo
    ./configure
    make
    
    # Store all outputs in /zig-out
    mkdir -p /zig-out/foo
    mv some_artifact /zig-out/foo/hi
    mv another_artifact /zig-out/bar


# my_repo/build.zig

    const sbox = alpine_zig.addSandboxBuild(b, .{
        // This build directory will be copied into the container.
        // It is expected to have an executable "build" that will
        // produce the specified outputs in /zig-out.
        .build_dir = .{ .path = "build_complex_thing" },
        .outputs = &[_][]const u8{
            "foo/hi",
            "bar",
        },
        .target = target,
        .optimize = optimize,
    });

    // You can add additional arguments to the build script
    // sbox.script.addArg(...);

    const install_hi = b.addInstallFile(sbox.outputs[0], "hi");
    const install_bar = b.addInstallFile(sbox.outputs[1], "bar");