diff --git a/make/defs.mk b/make/defs.mk
index 73955079..0416764b 100644
--- a/make/defs.mk
+++ b/make/defs.mk
@@ -266,8 +266,11 @@ ifeq ($(USE_VALGRIND),true)
 	# PROJECT_LDFLAGS += 
 endif
 
-ifeq ($(USE_TIMER),true)
+# TODO: this shoud be only conditional, but breaks, because not all headers
+#       do a conditional include of timer headers, yet
 GENERATE_FUNC_TIMERS   = $(MODDIR)/YStopWatchThreadList/generate_func_timers.sh
+
+ifeq ($(USE_TIMER),true)
 CFLAGS                += -D_USE_TIMER_
 CPPFLAGS              += -D_USE_TIMER_
 endif