diff --git a/Makefile b/Makefile
index 09110e3..0099840 100644
--- a/Makefile
+++ b/Makefile
@@ -28,7 +28,7 @@ RUSTLIBS = --extern getopt=build/o/libgetopt.rlib \
 CFLAGS += -I$(SYSEXITS)
 
 .PHONY: all
-all: dj false fop hru intcmp mm npc rpn scrut str strcmp swab true
+all: dj false fop hru intcmp mm npc rpn scrut sleep str strcmp swab true
 
 build:
 	# keep build/include until bindgen(1) has stdin support