--- xlunch.c.orig	2017-05-17 21:38:59.048445309 -0500
+++ xlunch.c	2017-05-17 21:39:41.334944291 -0500
@@ -27,6 +27,9 @@
 #include <sys/file.h>
 #include <errno.h>
 
+/* file I/O stuff */
+#include <fcntl.h>
+
 /* some globals for our window & X display */
 Display *disp;
 Window   win;
