i can't think of anything else

diff --git a/src/libutil/unix/file-descriptor.cc b/src/libutil/unix/file-descriptor.cc
index 2b612e854..194dcb3b6 100644
--- a/src/libutil/unix/file-descriptor.cc
+++ b/src/libutil/unix/file-descriptor.cc
@@ -6,6 +6,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <poll.h>
+#include <sys/syscall.h>
 
 #include "util-config-private.hh"
 #include "util-unix-config-private.hh"