diff --git a/vendor/golang.org/x/sys/unix/syscall_linux_amd64.go b/vendor/golang.org/x/sys/unix/syscall_linux_amd64.go
index 87a3074..088ce0f 100644
--- a/vendor/golang.org/x/sys/unix/syscall_linux_amd64.go
+++ b/vendor/golang.org/x/sys/unix/syscall_linux_amd64.go
@@ -163,6 +163,10 @@
 	msghdr.Controllen = uint64(length)
 }
 
+func (msghdr *Msghdr) SetIovlen(length int) {
+	msghdr.Iovlen = uint64(length)
+}
+
 func (cmsg *Cmsghdr) SetLen(length int) {
 	cmsg.Len = uint64(length)
 }