SEBA-829 update cordctl to use go mod;
implement run, install, help

Change-Id: I72716d2e245d5ef0dc0603aad149843723ddff9e
diff --git a/vendor/golang.org/x/sys/unix/env_unix.go b/vendor/golang.org/x/sys/unix/env_unix.go
new file mode 100644
index 0000000..84178b0
--- /dev/null
+++ b/vendor/golang.org/x/sys/unix/env_unix.go
@@ -0,0 +1,31 @@
+// Copyright 2010 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 dragonfly freebsd linux netbsd openbsd solaris
+
+// Unix environment variables.
+
+package unix
+
+import "syscall"
+
+func Getenv(key string) (value string, found bool) {
+	return syscall.Getenv(key)
+}
+
+func Setenv(key, value string) error {
+	return syscall.Setenv(key, value)
+}
+
+func Clearenv() {
+	syscall.Clearenv()
+}
+
+func Environ() []string {
+	return syscall.Environ()
+}
+
+func Unsetenv(key string) error {
+	return syscall.Unsetenv(key)
+}