diff --git a/libraries/physics/CMakeLists.txt b/libraries/physics/CMakeLists.txt
index 8b6025aa1d..ec289cd096 100644
--- a/libraries/physics/CMakeLists.txt
+++ b/libraries/physics/CMakeLists.txt
@@ -12,7 +12,7 @@ find_package(Bullet)
 if (BULLET_FOUND)
     include_directories(SYSTEM "${BULLET_INCLUDE_DIRS}")
     list(APPEND ${TARGET_NAME}_LIBRARIES_TO_LINK "${BULLET_LIBRARIES}")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DUSE_BULLET_PHYSICS}")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DUSE_BULLET_PHYSICS")
 endif (BULLET_FOUND)
 
 # call macro to link our dependencies and bubble them up via a property on our target