dotnet/aspnetcore: Fix AppHost pack prebuilt usage in source-build

src/SourceBuild/tarball/patches/aspnetcore/0006-Fix-AppHost-pack-prebuilt-usage-in-source-build.patch

@@ -0,0 +1,41 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Davis Goodin <dagood@microsoft.com>
+Date: Mon, 18 Oct 2021 18:45:16 -0500
+Subject: [PATCH] Fix AppHost pack prebuilt usage in source-build
+
+This avoids downloading a prebuilt apphost pack.
+
+Upstream PR: https://github.com/dotnet/aspnetcore/pull/37672
+---
+ Directory.Build.props | 18 +++++++++++++++---
+ 1 file changed, 15 insertions(+), 3 deletions(-)
+
+diff --git a/Directory.Build.props b/Directory.Build.props
+index dc1f355411..e2dea35567 100644
+--- a/Directory.Build.props
++++ b/Directory.Build.props
+@@ -197,9 +197,21 @@
+
+   <!-- The location of the local installation of the .NET Core shared framework. -->
+   <PropertyGroup>
+-    <LocalDotNetRoot>$(RepoRoot).dotnet\</LocalDotNetRoot>
+-    <!-- Override the SDK default and point to local .dotnet folder. -->
+-    <NetCoreTargetingPackRoot>$(LocalDotNetRoot)packs\</NetCoreTargetingPackRoot>
++    <!--
++      Override the SDK default and point to local .dotnet folder. This is required to work around
++      several limitations in the way the .NET SDK finds shared frameworks and targeting packs. It
++      allows tests to use shared frameworks and targeting packs.
++
++      However, source-build needs this to not happen while building projects that rely on the
++      AppHost framework pack. Source-build installs an SDK in a custom location outside this
++      repository, and setting NetCoreTargetingPackRoot to a different location causes source-build
++      to restore the AppHost pack as a prebuilt rather than using the one that's present in the SDK.
++
++      This condition still allows the Microsoft.AspNetCore.App.Ref and .Runtime projects to publish
++      to this location, so they don't modify the existing SDK being used by source-build.
++    -->
++    <LocalDotNetRoot Condition="'$(DotNetBuildFromSource)' != 'true' or '$(UseAppHost)' != 'true'">$(RepoRoot).dotnet\</LocalDotNetRoot>
++    <NetCoreTargetingPackRoot Condition="'$(LocalDotNetRoot)' != ''">$(LocalDotNetRoot)packs\</NetCoreTargetingPackRoot>
+   </PropertyGroup>
+
+   <Import Project="eng\tools\RepoTasks\RepoTasks.tasks" Condition="'$(MSBuildProjectName)' != 'RepoTasks' AND '$(DesignTimeBuild)' != 'true'" />