diff --git a/io/iob_send.c b/io/iob_send.c
index 96e70c7..6f77618 100644
--- a/io/iob_send.c
+++ b/io/iob_send.c
@@ -16,6 +16,7 @@ int64 iob_send(int64 s,io_batch* b) {
   long i;
   long headers;
 #ifdef HAVE_BSDSENDFILE
+#define SENDFILE 1
   long trailers;
 #endif