Merge topic 'FindBoost-link-threads'

bd831ed094 FindBoost: Add system thread library to Boost_LIBRARIES

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !2570

Modules/FindBoost.cmake

@@ -2082,6 +2082,9 @@ if(Boost_FOUND)
         message (STATUS "  ${COMPONENT}")
       endif()
       list(APPEND Boost_LIBRARIES ${Boost_${UPPERCOMPONENT}_LIBRARY})
+      if(COMPONENT STREQUAL "thread")
+        list(APPEND Boost_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
+      endif()
     endif()
   endforeach()
 else()