if(NOT APPLE)
  find_library(LIBRT_LIBRARIES rt)
  mark_as_advanced(LIBRT_LIBRARIES)
  if(NOT LIBRT_LIBRARIES)
    message(FATAL_ERROR "Could not find librt")
  endif()
else()
  set(LIBRT_LIBRARIES "")
endif()

find_package(Threads REQUIRED)

find_library(LIBM_LIBRARIES m)
mark_as_advanced(LIBM_LIBRARIES)
if(NOT LIBM_LIBRARIES)
  message(FATAL_ERROR "Could not find libm")
endif()