diff --git a/make/rules.mk b/make/rules.mk
index 9418f6d3..5b14e9d1 100644
--- a/make/rules.mk
+++ b/make/rules.mk
@@ -158,6 +158,10 @@ echo-include:
 echo-mk:
 	@echo MAKEFILE_LIST = $(MAKEFILE_LIST)
 
+echo-prereq:
+	@echo PREREQ_BUILD      = $(sort $(PREREQ_BUILD))
+	@echo PREREQ_INSTALL    = $(sort $(PREREQ_INSTALL))
+
 echo-contrib:
 
 trace-marks: