diff --git a/sic.c b/sic.c
index ecefaf2..774f357 100644
--- a/sic.c
+++ b/sic.c
@@ -1,4 +1,6 @@
  /* See LICENSE file for license details. */
+#include <sys/select.h>
+
 #include <ctype.h>
 #include <errno.h>
 #include <stdarg.h>