libDirFromInstallationPath

    fn libDirFromInstallationPath(
        gpa: Allocator,
        io: Io,
        installation_path: []const u8,
        arch: std.Target.Cpu.Arch,
    ) error{ OutOfMemory, PathNotFound }![]const u8 {
        var lib_dir_buf = try std.array_list.Managed(u8).initCapacity(gpa, installation_path.len + 64);
        errdefer lib_dir_buf.deinit();

        lib_dir_buf.appendSliceAssumeCapacity(installation_path);

        if (!Dir.path.isSep(lib_dir_buf.last().?)) {
            try lib_dir_buf.append('\\');
        }
        const installation_path_with_trailing_sep_len = lib_dir_buf.items.len;

        try lib_dir_buf.appendSlice("VC\\Auxiliary\\Build\\Microsoft.VCToolsVersion.default.txt");
        var default_tools_version_buf: [512]u8 = undefined;
        const default_tools_version_contents = Dir.cwd().readFile(io, lib_dir_buf.items, &default_tools_version_buf) catch {
            return error.PathNotFound;
        };
        var tokenizer = std.mem.tokenizeAny(u8, default_tools_version_contents, " \r\n");
        const default_tools_version = tokenizer.next() orelse return error.PathNotFound;

        lib_dir_buf.shrinkRetainingCapacity(installation_path_with_trailing_sep_len);
        try lib_dir_buf.appendSlice("VC\\Tools\\MSVC\\");
        try lib_dir_buf.appendSlice(default_tools_version);
        try lib_dir_buf.appendSlice("\\Lib\\");
        try lib_dir_buf.appendSlice(switch (arch) {
            .thumb => "arm",
            .aarch64 => "arm64",
            .x86 => "x86",
            .x86_64 => "x64",
            else => unreachable,
        });

        if (!verifyLibDir(io, lib_dir_buf.items)) {
            return error.PathNotFound;
        }

        return lib_dir_buf.toOwnedSlice();
    }