+ifneq ($(strip $(VARIABLE_TRACE)),)
+ SRC += $(QUANTUM_DIR)/variable_trace.c
+ OPT_DEFS += -DNUM_TRACED_VARIABLES=$(strip $(VARIABLE_TRACE))
+ifneq ($(strip $(MAX_VARIABLE_TRACE_SIZE)),)
+ OPT_DEFS += -DMAX_VARIABLE_TRACE_SIZE=$(strip $(MAX_VARIABLE_TRACE_SIZE))
+endif
+endif
+