diff --git a/src/mm.c b/src/mm.c
index 231985d..01fd400 100644
--- a/src/mm.c
+++ b/src/mm.c
@@ -24,8 +24,8 @@
 #include <stdlib.h> /* free(3), realloc(3) */
 #include <string.h> /* strcmp(3), strerror(3) */
 #include <unistd.h> /* getopt(3) */
-#include <sysexits.h>
-#endif
+#include <sysexits.h> /* EX_IOERR, EX_OK, EX_OSERR, EX_USAGE */
+
 extern int errno;
 
 /* This structure is how open files are tracked. */