Add System.Runtime.Versioning attributes

Author: andrewlock

tracer/src/Datadog.Trace/Util/System.Runtime.Versioning.Attributes.cs

@@ -0,0 +1,26 @@
+// <copyright file="System.Runtime.Versioning.Attributes.cs" company="Datadog">
+// Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
+// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
+// </copyright>
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// https://github.com/dotnet/runtime/blob/bffa7cf52b3982597adc5447c25e7aaa3b063c1c/src/libraries/System.Private.CoreLib/src/System/Diagnostics/CodeAnalysis/NullableAttributes.cs
+
+// This file contains attributes from the System.Runtime.Versioning namespace
+// used by the compiler for compiler-y stuff.
+
+#nullable enable
+
+#pragma warning disable SA1649 // file name should match first type name
+#pragma warning disable SA1402 // file may only contain a single type
+
+// ReSharper disable once CheckNamespace
+namespace System.Runtime.Versioning;
+
+// This attribute is used by some vendored Microsoft code
+// https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/readytorun-overview.md#performance-impact-1
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Constructor | AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
+internal sealed class NonVersionableAttribute : Attribute
+{
+}