diff --git a/lib/system/mmdisp.nim b/lib/system/mmdisp.nim
index 63af49e35b..431f84bfd4 100644
--- a/lib/system/mmdisp.nim
+++ b/lib/system/mmdisp.nim
@@ -20,7 +20,7 @@ const
   alwaysCycleGC = defined(smokeCycles)
   alwaysGC = defined(fulldebug) # collect after every memory
                                 # allocation (for debugging)
-  leakDetector = false
+  leakDetector = defined(leakDetector)
   overwriteFree = defined(nimBurnFree) # overwrite memory with 0xFF before free
   trackAllocationSource = leakDetector