Allow using VS to run host tests when libraries use different config

docs/workflow/testing/host/testing.md

@@ -77,6 +77,11 @@ The `category!=failing` is to respect the [filtering traits](../libraries/filter
 ### Visual Studio
 
 The [Microsoft.DotNet.CoreSetup.sln](/src/installer/Microsoft.DotNet.CoreSetup.sln) can be used to run and debug host tests through Visual Studio. When using the solution, the product should have already been [built](#building-tests) and the [test context](#test-context) set up.
+If you built the runtime or libraries with a different configuration from the host, you have to specify this when starting visual studio:
+
+```console
+build.cmd -vs Microsoft.DotNet.CoreSetup -rc Release -lc Release
+```
 
 ### Preserving test artifacts
 

eng/build.ps1

@@ -234,6 +234,12 @@ if ($vs) {
     $env:RUNTIMECONFIGURATION=$runtimeConfiguration
   }
 
+  if ($librariesConfiguration)
+  {
+    # Respect the RuntimeConfiguration variable for building inside VS with different libraries configurations
+    $env:LIBRARIESCONFIGURATION=$librariesConfiguration
+  }
+
   # Launch Visual Studio with the locally defined environment variables
   ."$vs"
 

eng/generators.targets

@@ -3,6 +3,8 @@
   <PropertyGroup>
     <EnableLibraryImportGenerator Condition="'$(EnableLibraryImportGenerator)' == '' and
                                              '$(MSBuildProjectName)' == 'System.Private.CoreLib'">true</EnableLibraryImportGenerator>
+
+    <ShouldUnsetParentConfigurationAndPlatform>false</ShouldUnsetParentConfigurationAndPlatform>
   </PropertyGroup>
 
   <ItemGroup>