--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgo/go/internal/poll/fcntl_libc.go	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,26 @@
+// Copyright 2019 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.
+
+// +build aix darwin solaris
+
+package poll
+
+import (
+	"syscall"
+)
+
+// Use a helper function to call fcntl.  This is defined in C in
+// libgo/runtime.
+//extern __go_fcntl_uintptr
+func libc_fcntl(uintptr, uintptr, uintptr) (uintptr, uintptr)
+
+func fcntl(fd int, cmd int, arg int) (int, error) {
+	syscall.Entersyscall()
+	r, e := libc_fcntl(uintptr(fd), uintptr(cmd), uintptr(arg))
+	syscall.Exitsyscall()
+	if e != 0 {
+		return int(r), syscall.Errno(e)
+	}
+	return int(r), nil
+}