Add shim start for shim creation

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

runtime/v2/shim/util_unix.go

@@ -0,0 +1,34 @@
+// +build !linux,!windows
+
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package shim
+
+import (
+	"syscall"
+)
+
+func getSysProcAttr() *syscall.SysProcAttr {
+	return &syscall.SysProcAttr{
+		Setpgid: true,
+	}
+}
+
+// SetScore sets the oom score for a process
+func SetScore(pid int) error {
+	return nil
+}