diff --git a/unix/syscall_dragonfly.go b/unix/syscall_dragonfly.go
index bed7dcf..842ab5a 100644
--- a/unix/syscall_dragonfly.go
+++ b/unix/syscall_dragonfly.go
@@ -47,6 +47,10 @@
 	raw    RawSockaddrDatalink
 }
 
+func anyToSockaddrGOOS(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
+	return nil, EAFNOSUPPORT
+}
+
 // Translate "kern.hostname" to []_C_int{0,1,2,3}.
 func nametomib(name string) (mib []_C_int, err error) {
 	const siz = unsafe.Sizeof(mib[0])