Remove MRT Core .props/.targets files

BuildAll.ps1

@@ -315,10 +315,6 @@ Try {
         Copy-Item -path "$MRTSourcesDirectory\mrt\Microsoft.Windows.ApplicationModel.Resources\src\Microsoft.Windows.ApplicationModel.Resources.idl" -destination "$BasePath\include" -force
 
         # Copy MRT metadata files.
-        Copy-Item -Path "$MRTSourcesDirectory\packaging\MrtCore.props" -Destination "$BasePath\build"
-        Copy-Item -Path "$MRTSourcesDirectory\packaging\MrtCore.PriGen.targets" -Destination "$BasePath\build"
-        Copy-Item -Path "$MRTSourcesDirectory\packaging\MrtCore.References.targets" -Destination "$BasePath\build"
-        Copy-Item -Path "$MRTSourcesDirectory\packaging\MrtCore.targets" -Destination "$BasePath\build"
         Copy-Item -Path "$MRTSourcesDirectory\packaging\native\MrtCore.C.props" -Destination "$BasePath\build\native"
         Copy-Item -Path "$MRTSourcesDirectory\packaging\native\MrtCore.props" -Destination "$BasePath\build\native"
         Copy-Item -Path "$MRTSourcesDirectory\packaging\native\MrtCore.targets" -Destination "$BasePath\build\native"

build/NuSpecs/Microsoft.WindowsAppSDK.Foundation.props

@@ -8,10 +8,4 @@
     <WindowsAppSdkFoundation>true</WindowsAppSdkFoundation>
   </PropertyGroup>
 
-  <!--
-    Ideally, this import would be done only if EnableCoreMrtTooling is true. That's impossible though because that
-    property cannot be defined beforehand.
-  -->
-  <Import Project="$(MSBuildThisFileDirectory)MrtCore.props" />
-
 </Project>

build/NuSpecs/Microsoft.WindowsAppSDK.Foundation.targets

@@ -2,8 +2,6 @@
 <!-- Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT License. See LICENSE in the project root for license information. -->
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
-  <Import Project="$(MSBuildThisFileDirectory)MrtCore.targets" />
-
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.BootstrapCommon.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.Bootstrap.CS.targets" Condition="'$(WindowsAppSdkBootstrapInitialize)' == 'true'"/>
 

dev/MRTCore/packaging/README.md

@@ -1,2 +1,3 @@
-MrtCore.targets generates PRIs in unpackaged app projects and unpackaged library projects.
-MrtCore.targets consists of some of the targets from the in-box file Microsoft.AppxPackage.Targets, with a few modified slightly.
+All .props/.targets files here have been moved to https://www.nuget.org/packages/Microsoft.Windows.SDK.BuildTools.MSIX.
+
+Only some .props for native projects are left here, as they depend on 'mrm.dll', which is part of WindowsAppSDK.