diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 8bef70fc7..2ed3a04d2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -328,8 +328,8 @@ set(LEAN_LIBS ${LEAN_LIBS} leanlua)
 add_subdirectory(init)
 set(LEAN_LIBS ${LEAN_LIBS} init)
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${LEAN_EXTRA_LINKER_FLAGS}")
-if(MULTI_THREAD AND (NOT (("${CMAKE_SYSTEM_NAME}" MATCHES "Darwin") AND BOOST)))
-   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pthread")
+if(MULTI_THREAD AND (NOT ("${CMAKE_SYSTEM_NAME}" MATCHES "Darwin")) AND (NOT BOOST))
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pthread")
 endif()
 set(CMAKE_EXE_LINKER_FLAGS_TESTCOV "${CMAKE_EXE_LINKER_FLAGS} -fprofile-arcs -ftest-coverage")
 set(ALL_LIBS ${LEAN_LIBS} ${EXTRA_LIBS})