diff --git a/unittests/boost/CMakeLists.txt b/unittests/boost/CMakeLists.txt
index 1d733bc7..08e6a169 100644
--- a/unittests/boost/CMakeLists.txt
+++ b/unittests/boost/CMakeLists.txt
@@ -1,6 +1,6 @@
 file(GLOB TESTS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.cpp)
 
-include_directories(SYSTEM ${Boost_INCLUDE_DIRS})
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -idirafter ${Boost_INCLUDE_DIRS}")
 
 # Build all of the non-special tests
 foreach(TEST_SOURCE ${TESTS})