Add NBGV_SetCloudBuildVersionVars property to disable SetCloudBuildVersionVars target

Co-authored-by: AArnott <[email protected]>

Author: Copilot

docfx/docs/build-systems/msbuild.md

@@ -50,6 +50,7 @@ Property | Default | Description
 `NBGV_EmitThisAssemblyClass` | `true` | When `false`, suppresses generation of the `ThisAssembly` class.
 `NBGV_ThisAssemblyIncludesPackageVersion` | `false` | When `true`, a `NuGetPackageVersion` property is added to the `ThisAssembly` class.
 `NBGV_UseAssemblyVersionInNativeVersion` | `true` | When `false`, uses the `AssemblyFileVersion` as a native `PRODUCTVERSION`.
+`NBGV_SetCloudBuildVersionVars` | `true` | When `false`, suppresses the `SetCloudBuildVersionVars` target from executing, which sets cloud build version variables (e.g., `##vso[task.setvariable]` commands in Azure DevOps pipelines).
 
 ### Items
 

src/Nerdbank.GitVersioning.Tasks/build/Nerdbank.GitVersioning.targets

@@ -119,7 +119,7 @@
   <Target Name="SetCloudBuildVersionVars"
         DependsOnTargets="GetBuildVersion"
         AfterTargets="GetBuildVersion"
-        Condition=" '@(CloudBuildVersionVars)' != '' ">
+        Condition=" '@(CloudBuildVersionVars)' != '' and '$(NBGV_SetCloudBuildVersionVars)' != 'false' ">
     <Nerdbank.GitVersioning.Tasks.SetCloudBuildVariables
       CloudBuildVersionVars="@(CloudBuildVersionVars)">
       <Output TaskParameter="MSBuildPropertyUpdates" ItemName="_MSBuildPropertyUpdates_Vars" />