diff --git a/Makefile.inc1 b/Makefile.inc1
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -3712,7 +3712,7 @@
 list-old-dirs: .PHONY
 	@cd ${.CURDIR}; \
 	${MAKE} -f ${.CURDIR}/Makefile.inc1 ${.MAKEFLAGS} ${.TARGET} \
-	    -V OLD_DIRS | sed -E 's/[[:space:]]+/\n/g' | sort -r
+	    -V "OLD_DIRS:ts\n" | sort -r
 
 delete-old-dirs: .PHONY
 	@echo ">>> Removing old directories"