Use .targets to replace file in NuGet package - nuget

Question

I have a NuGet package that depends on another NuGet package but I want to replace one of the unmanaged DLLs with one of mine. This works well, but now I'm trying to add support for both x86 and x64 using a .targets file. When my target application builds, it pulls down the original version, not the replacement.
Here's my .nuspec:
<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
<metadata>
<id>MyPackage</id>
<version>2.0.0</version>
<dependencies>
<group targetFramework=".NETFramework4.5.2">
<dependency id="YourPackage" version="1.0.0" />
</group>
</dependencies>
</metadata>
<files>
<file src="MyPackage.targets" target="build\net452" />
<file src="..\lib\x86\thepackage.dll" target="lib\net452\x86" />
<file src="..\lib\x64\thepackage.dll" target="lib\net452\x64" />
</files>
</package>
Here's my .targets:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Target Name="PlatformCheck" BeforeTargets="InjectReference"
Condition="(('$(Platform)' != 'x86') AND ('$(Platform)' != 'x64'))">
<Error Text="$(MSBuildThisFileName) does not work correctly on '$(Platform)' platform. You need to specify platform (x86 or x64)." />
</Target>
<Target Name="InjectReference" AfterTargets="ResolveAssemblyReferences">
<ItemGroup Condition="'$(Platform)' == 'x86' or '$(Platform)' == 'x64'">
<Reference Include="MyPackage">
<HintPath>$(MSBuildThisFileDirectory)$(Platform)\thepackage.dll</HintPath>
</Reference>
</ItemGroup>
</Target>
</Project>
What am I doing wrong?
EDIT: If I change the .nuspec...
<file src="..\lib\x86\thepackage.dll" target="lib\net452" />
<file src="..\lib\x64\thepackage.dll" target="lib\net452" />
... then it pulls down my version but uses x86 for both x86 and x64 builds.

Answer 1

I solved it by putting the files in the build folder and then simply copying the target file.
.nuspec:
<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
<metadata>
<id>MyPackage</id>
<version>2.0.0</version>
<dependencies>
<group targetFramework=".NETFramework4.5.2">
<dependency id="YourPackage" version="1.0.0" />
</group>
</dependencies>
</metadata>
<files>
<file src="MyPackage.targets" target="build\net452" />
<file src="..\lib\x86\thepackage.dll" target="build\net452\x86" />
<file src="..\lib\x64\thepackage.dll" target="build\net452\x64" />
</files>
</package>
.targets:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Target Name="PlatformCheck" BeforeTargets="InjectReference"
Condition="(('$(Platform)' != 'x86') AND ('$(Platform)' != 'x64'))">
<Error Text="$(MSBuildThisFileName) does not work correctly on '$(Platform)' platform. You need to specify platform (x86 or x64)." />
</Target>
<ItemGroup>
<None Include="$(MSBuildThisFileDirectory)$(Platform)\thepackage.dll">
<Link>%(RecursiveDir)%(FileName)%(Extension)</Link>
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</None>
</ItemGroup>
</Project>