diff --git a/make/dirs.mk b/make/dirs.mk
index ac8f06d5..e9f67739 100644
--- a/make/dirs.mk
+++ b/make/dirs.mk
@@ -21,7 +21,7 @@ else
 SUBDIR_TARGETS = $(filter all install clean distclean,$(MAKECMDGOALS))
 endif
 
-PREREQ_DIRS_DONE = $(addsuffix /dirs-all.done,$(filter-out $(TOPDIR),$(foreach p,$(PREREQ),$($(p)_DIR))))
+PREREQ_DIRS_DONE = $(addsuffix /dirs-all.done,$(filter-out $(TOPDIR) /opt/%,$(foreach p,$(PREREQ),$($(p)_DIR))))
 
 all: dirs-all.done
 install: dirs-install.done