[libc++] Include headers in <thread> conditionally

Author: philnik777

libcxx/include/thread

@@ -90,11 +90,17 @@ void sleep_for(const chrono::duration<Rep, Period>& rel_time);
 
 #if _LIBCPP_HAS_THREADS
 
-#  include <__thread/formatter.h>
-#  include <__thread/jthread.h>
-#  include <__thread/support.h>
 #  include <__thread/this_thread.h>
 #  include <__thread/thread.h>
+
+#  if _LIBCPP_STD_VER >= 20
+#    include <__thread/jthread.h>
+#  endif
+
+#  if _LIBCPP_STD_VER >= 23
+#    include <__thread/formatter.h>
+#  endif
+
 #  include <version>
 
 // standard-mandated includes
@@ -108,13 +114,6 @@ void sleep_for(const chrono::duration<Rep, Period>& rel_time);
 
 #endif // _LIBCPP_HAS_THREADS
 
-#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES)
-#  include <cstddef>
-#  include <ctime>
-#  include <iosfwd>
-#  include <ratio>
-#endif
-
 #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 17
 #  include <chrono>
 #endif