diff --git a/implementations/C/Makefile b/implementations/C/Makefile
index 5525702..9a6af02 100644
--- a/implementations/C/Makefile
+++ b/implementations/C/Makefile
@@ -15,11 +15,15 @@ GPERF_OPTS = --readonly-tables --enum --includes --hash-function-name=keyword_ha
 
 joy: ${OBJS} $(STATIC_GCLIB)
 
+joy.o: joy.h
+
+
 # Gperf doesn't add anything to '{""}' unused entries in the wordlist.
 # This causes "warning: missing field 'func' initializer [-Wmissing-field-initializers]"
 # which is promoted to an error and holds up the show.
 # But we can turn off that warning for the keyword code like so:
 keywords.o: CFLAGS+=-Wno-missing-field-initializers
+keywords.o: joy.h
 
 keywords.c: KEYWORDS.txt
 	gperf --output-file=$@ $(GPERF_OPTS) $<