diff --git a/include/Makefile.in b/include/Makefile.in
index 23bc89f24..80e7e876d 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -135,3 +135,4 @@ bits.h: bits
 bits: bits.o
 	$(CC) -o bits bits.o
 
+bits.o: bits.c