cmake: remove fileset workaround

CMakeLists.txt

@@ -8,15 +8,11 @@ cmake_minimum_required(VERSION 3.5...3.16)
 project(boost_lockfree VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
 option(BOOST_LOCKFREE_BUILD_TESTS "Build boost::lockfree tests" OFF)
-option(BOOST_LOCKFREE_USE_FILE_SET "Use FILE_SET for boost::lockfree" OFF)
-
 
 add_library(boost_lockfree INTERFACE)
 add_library(Boost::lockfree ALIAS boost_lockfree)
 
-target_include_directories(boost_lockfree INTERFACE include)
-
-if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.23 AND BOOST_LOCKFREE_USE_FILE_SET)
+if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.23)
     set(Headers
         include/boost/lockfree/spsc_queue.hpp
         include/boost/lockfree/policies.hpp
@@ -33,7 +29,9 @@ if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.23 AND BOOST_LOCKFREE_USE_FILE_SET)
         include/boost/lockfree/stack.hpp
     )
 
-    target_sources(boost_lockfree PUBLIC FILE_SET HEADERS FILES ${Headers} )
+    target_sources(boost_lockfree PUBLIC FILE_SET HEADERS BASE_DIRS include FILES ${Headers} )
+else()
+    target_include_directories(boost_lockfree INTERFACE include)
 endif()
 
 target_link_libraries(boost_lockfree