diff --git a/SabreTools.Serialization/SabreTools.Serialization.csproj b/SabreTools.Serialization/SabreTools.Serialization.csproj
index 8c232075..dd210262 100644
--- a/SabreTools.Serialization/SabreTools.Serialization.csproj
+++ b/SabreTools.Serialization/SabreTools.Serialization.csproj
@@ -26,14 +26,30 @@
         <PackageLicenseExpression>MIT</PackageLicenseExpression>
     </PropertyGroup>
 
-    <ItemGroup>
-        <InternalsVisibleTo Include="SabreTools.Serialization.Test" />
-    </ItemGroup>
+    <!-- Set build flags for Windows specifically -->
+    <PropertyGroup Condition="'$(RuntimeIdentifier)'=='win-x86'">
+        <DefineConstants>$(DefineConstants);WINX86</DefineConstants>
+    </PropertyGroup>
+    <PropertyGroup Condition="'$(RuntimeIdentifier)'=='win-x64'">
+        <DefineConstants>$(DefineConstants);WINX64</DefineConstants>
+    </PropertyGroup>
 
     <ItemGroup>
         <None Include="../README.md" Pack="true" PackagePath="" />
     </ItemGroup>
 
+    <!-- These are needed for dealing with native Windows DLLs -->
+    <ItemGroup>
+        <Content Include="runtimes\**\*">
+            <PackagePath>%(Identity)</PackagePath>
+            <Pack>true</Pack>
+        </Content>
+    </ItemGroup>
+
+    <ItemGroup>
+        <InternalsVisibleTo Include="SabreTools.Serialization.Test" />
+    </ItemGroup>
+
     <ItemGroup>
         <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
         <PackageReference Include="SabreTools.ASN1" Version="1.6.0" />