findViaVs7Key

    fn findViaVs7Key(
        gpa: Allocator,
        io: Io,
        registry: *Registry,
        arch: std.Target.Cpu.Arch,
        environ_map: *const Environ.Map,
    ) error{ OutOfMemory, PathNotFound }![]const u8 {
        var base_path: std.array_list.Managed(u8) = base_path: {
            try_env: {
                if (environ_map.get("VS140COMNTOOLS")) |VS140COMNTOOLS| {
                    if (VS140COMNTOOLS.len < "C:\\Common7\\Tools".len) break :try_env;
                    if (!Dir.path.isAbsolute(VS140COMNTOOLS)) break :try_env;
                    var list = std.array_list.Managed(u8).init(gpa);
                    errdefer list.deinit();

                    try list.appendSlice(VS140COMNTOOLS); // C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\Tools
                    // String might contain trailing slash, so trim it here
                    if (list.items.len > "C:\\".len and list.last().? == '\\') _ = list.pop();
                    list.shrinkRetainingCapacity(list.items.len - "\\Common7\\Tools".len); // C:\Program Files (x86)\Microsoft Visual Studio 14.0
                    break :base_path list;
                }
            }

            const vs7_key = registry.openSoftwareKey(.{ .root = .local_machine, .wow64 = .wow64_32 }, L("Microsoft\\VisualStudio\\SxS\\VS7")) catch return error.PathNotFound;
            defer vs7_key.close();
            try_vs7_key: {
                const path_maybe_with_trailing_slash = vs7_key.getString(gpa, .{ .name = L("14.0") }, .wtf8) catch |err| switch (err) {
                    error.OutOfMemory => |e| return e,
                    else => break :try_vs7_key,
                };

                if (path_maybe_with_trailing_slash.len > Dir.max_path_bytes or !Dir.path.isAbsolute(path_maybe_with_trailing_slash)) {
                    gpa.free(path_maybe_with_trailing_slash);
                    break :try_vs7_key;
                }

                var path = std.array_list.Managed(u8).fromOwnedSlice(gpa, path_maybe_with_trailing_slash);
                errdefer path.deinit();

                // String might contain trailing slash, so trim it here
                if (path.items.len > "C:\\".len and path.last().? == '\\') _ = path.pop();
                break :base_path path;
            }
            return error.PathNotFound;
        };
        errdefer base_path.deinit();

        try base_path.appendSlice("\\VC\\lib\\");
        try base_path.appendSlice(switch (arch) {
            .thumb => "arm",
            .aarch64 => "arm64",
            .x86 => "", //x86 is in the root of the Lib folder
            .x86_64 => "amd64",
            else => unreachable,
        });

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

        const full_path = try base_path.toOwnedSlice();
        return full_path;
    }