diff --git a/1986/hague/Makefile b/1986/hague/Makefile
index ea651b724..ed25d6a49 100644
--- a/1986/hague/Makefile
+++ b/1986/hague/Makefile
@@ -62,7 +62,7 @@ CDEFINE=
 
 # Include files that are needed to compile
 #
-CINCLUDE=
+CINCLUDE= -include stdio.h -include unistd.h
 
 # Optimization
 #