WIP [VOL-2811] - Incorporate preliminary onu-adapter-go code into opencord repo

- reason "discovery-mibsync-complete" reached (via full MibUpload only, received data won't be stored yet)
- first review comments of patchset #4 considered
 (please have a look into our inline-comments in Gerrit to know more about the current state)
- no refactoring done yet

Change-Id: Iac47817f8ce4bd28dd8132f530b0570d57ae99b8
Signed-off-by: Holger Hildebrandt <holger.hildebrandt@adtran.com>
diff --git a/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.go b/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.go
new file mode 100644
index 0000000..6a15cba
--- /dev/null
+++ b/vendor/golang.org/x/sys/unix/syscall_darwin.1_12.go
@@ -0,0 +1,29 @@
+// 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 darwin,go1.12,!go1.13
+
+package unix
+
+import (
+	"unsafe"
+)
+
+func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
+	// To implement this using libSystem we'd need syscall_syscallPtr for
+	// fdopendir. However, syscallPtr was only added in Go 1.13, so we fall
+	// back to raw syscalls for this func on Go 1.12.
+	var p unsafe.Pointer
+	if len(buf) > 0 {
+		p = unsafe.Pointer(&buf[0])
+	} else {
+		p = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_GETDIRENTRIES64, uintptr(fd), uintptr(p), uintptr(len(buf)), uintptr(unsafe.Pointer(basep)), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		return n, errnoErr(e1)
+	}
+	return n, nil
+}