Add WasmImportLinkageAttribute (#93823)

* Add WasmImportLinkageAttribute

---------

Co-authored-by: Aaron R Robinson <arobins@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -1023,6 +1023,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\UnmanagedType.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\VarEnum.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\VariantWrapper.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\WasmImportLinkageAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\ISimdVector_2.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\Scalar.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\Intrinsics\SimdVectorExtensions.cs" />
@@ -2736,4 +2737,4 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\IUnaryPlusOperators.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\IUnsignedNumber.cs" />
   </ItemGroup>
-</Project>
+</Project>

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/WasmImportLinkageAttribute.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.InteropServices
+{
+    /// <summary>
+    /// Specifies that the P/Invoke marked with this attribute should be linked in as a WASM import.
+    /// </summary>
+    /// <remarks>
+    /// See https://webassembly.github.io/spec/core/syntax/modules.html#imports.
+    /// </remarks>
+    [AttributeUsage(AttributeTargets.Method, Inherited = false)]
+    public sealed class WasmImportLinkageAttribute : Attribute
+    {
+        /// <summary>
+        /// Instance constructor.
+        /// </summary>
+        public WasmImportLinkageAttribute() { }
+    }
+}

src/libraries/System.Runtime.InteropServices/ref/System.Runtime.InteropServices.cs

@@ -1728,6 +1728,11 @@ public sealed partial class VariantWrapper
         public VariantWrapper(object? obj) { }
         public object? WrappedObject { get { throw null; } }
     }
+    [System.AttributeUsageAttribute(System.AttributeTargets.Method, Inherited = false)]
+    public sealed class WasmImportLinkageAttribute : Attribute
+    {
+        public WasmImportLinkageAttribute() { }
+    }
 }
 namespace System.Runtime.InteropServices.ComTypes
 {