diff --git a/CMakeLists.txt b/CMakeLists.txt
index f69a3049a..960f30694 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -183,4 +183,7 @@ if(WITH_TOOLS)
     target_link_libraries( osrm-io-benchmark ${Boost_LIBRARIES} GITDESCRIPTION)
     add_executable ( osrm-unlock-all Tools/unlock_all_mutexes.cpp )
     target_link_libraries( osrm-unlock-all ${Boost_LIBRARIES} GITDESCRIPTION)
+    if(UNIX AND NOT APPLE)
+        target_link_libraries( osrm-unlock-all rt )
+    endif(UNIX AND NOT APPLE)
 endif(WITH_TOOLS)