Regenerate CMakeLists.txt with boostdep --cmake optional

CMakeLists.txt

@@ -1,8 +1,10 @@
-# Copyright 2019 Mike Dev
+# Generated by `boostdep --cmake optional`
+# Copyright 2020, 2021 Peter Dimov
 # Distributed under the Boost Software License, Version 1.0.
-# See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
+# https://www.boost.org/LICENSE_1_0.txt
 
 cmake_minimum_required(VERSION 3.5...3.20)
+
 project(boost_optional VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
 add_library(boost_optional INTERFACE)
@@ -15,7 +17,6 @@ target_link_libraries( boost_optional
     Boost::assert
     Boost::config
     Boost::core
-        Boost::detail
     Boost::move
     Boost::predef
     Boost::static_assert
@@ -23,3 +24,9 @@ target_link_libraries( boost_optional
     Boost::type_traits
     Boost::utility
 )
+
+if(BUILD_TESTING AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt")
+
+  add_subdirectory(test)
+
+endif()