diff --git a/src/intcmp.c b/src/intcmp.c
index fc7e0e9..e5dcdec 100644
--- a/src/intcmp.c
+++ b/src/intcmp.c
@@ -18,9 +18,9 @@
 
 #include <errno.h> /* errno */
 #include <stdio.h> /* fprintf(3), stderr */
-#include <stdlib.h> /* strtol(3), size_t */
+#include <stdlib.h> /* strtol(3), size_t, EXIT_FAILURE */
 #ifndef EX_USAGE
-#	include <sysexits.h> /* EX_USAGE */
+#	define EX_USAGE EXIT_FAILURE
 #endif
 #include <unistd.h> /* getopt(3), optind */