aspnetcore: Binlog for tools, rm RTMVersion infra

The RTMVersion infra looks like it would bring in prebuilts. (It's just
a guess at a fix for RepoTasks.csproj.)

Author: dagood

patches/aspnetcore/0017-Emit-RepoTasks.binlog.patch

@@ -0,0 +1,25 @@
+From 8f63217ad54ec431e398753b2bf745a1eb565e36 Mon Sep 17 00:00:00 2001
+From: Davis Goodin <[email protected]>
+Date: Mon, 21 Dec 2020 14:37:58 -0600
+Subject: [PATCH] Emit RepoTasks.binlog
+
+Lets us diagnose errors that occur while building RepoTasks.csproj.
+---
+ build.sh | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/build.sh b/build.sh
+index 3c3cab39ce..029bb4f0c8 100755
+--- a/build.sh
++++ b/build.sh
+@@ -360,6 +360,7 @@ if [ "$build_repo_tasks" = true ]; then
+         -p:Restore=$run_restore \
+         -p:Build=true \
+         -clp:NoSummary \
++        -bl:RepoTasks.binlog \
+         ${toolset_build_args[@]+"${toolset_build_args[@]}"}
+ fi
+ 
+-- 
+2.25.4
+

patches/aspnetcore/0018-Don-t-use-RTMVersion-in-source-build.patch

@@ -0,0 +1,34 @@
+From 340b200c6f0efe8dbe38186a5c94ba28cd9bfd5f Mon Sep 17 00:00:00 2001
+From: Davis Goodin <[email protected]>
+Date: Mon, 21 Dec 2020 15:17:22 -0600
+Subject: [PATCH] Don't use RTMVersion in source-build
+
+This seems like it would bring in prebuilts, and more directly, causes:
+
+  Detected package downgrade: System.Security.Cryptography.Pkcs from 5.0.1 to 5.0.0. Reference the package directly from the project to select a different version. 
+   RepoTasks -> NuGet.Packaging 5.8.0-rc.6930 -> System.Security.Cryptography.Pkcs (>= 5.0.1) 
+   RepoTasks -> System.Security.Cryptography.Pkcs (>= 5.0.0)
+---
+ eng/Dependencies.props | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/eng/Dependencies.props b/eng/Dependencies.props
+index d573a7bde9..79436b5a16 100644
+--- a/eng/Dependencies.props
++++ b/eng/Dependencies.props
+@@ -198,7 +198,11 @@ and are generated based on the last package release.
+     <!-- Get versions. -->
+     <LatestPackageReference Update="@(LatestPackageReference)">
+       <Version>$(%(VersionName)PackageVersion)</Version>
+-      <RTMVersion>$(%(VersionName)V0PackageVersion)</RTMVersion>
++      <!--
++        Don't set RTMVersion if building from source. RTMVersion represents a downlevel version of
++        the package, which we don't have access to in source-build. (It would be a prebuilt.)
++      -->
++      <RTMVersion Condition="'$(DotNetBuildFromSource)' != 'true'">$(%(VersionName)V0PackageVersion)</RTMVersion>
+ 
+       <!-- Remove excess metadata. -->
+       <RTMVersion Condition=" '%(Version)' == '%(RTMVersion)' " />
+-- 
+2.25.4
+