diff --git a/vendor/golang.org/x/sys/unix/fcntl.go b/vendor/golang.org/x/sys/unix/fcntl.go
new file mode 100644
index 0000000..e9b9912
--- /dev/null
+++ b/vendor/golang.org/x/sys/unix/fcntl.go
@@ -0,0 +1,37 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build dragonfly || freebsd || linux || netbsd || openbsd
+// +build dragonfly freebsd linux netbsd openbsd
+
+package unix
+
+import "unsafe"
+
+// fcntl64Syscall is usually SYS_FCNTL, but is overridden on 32-bit Linux
+// systems by fcntl_linux_32bit.go to be SYS_FCNTL64.
+var fcntl64Syscall uintptr = SYS_FCNTL
+
+func fcntl(fd int, cmd, arg int) (int, error) {
+	valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg))
+	var err error
+	if errno != 0 {
+		err = errno
+	}
+	return int(valptr), err
+}
+
+// FcntlInt performs a fcntl syscall on fd with the provided command and argument.
+func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
+	return fcntl(int(fd), cmd, arg)
+}
+
+// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.
+func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
+	_, _, errno := Syscall(fcntl64Syscall, fd, uintptr(cmd), uintptr(unsafe.Pointer(lk)))
+	if errno == 0 {
+		return nil
+	}
+	return errno
+}