User Story 37654: Create Extensions base package

- Explicitly unsetting $PLATFORM and $CONFIGURATION since Extensions doesn't need them.

Author: paulmedynski

.editorconfig

@@ -163,7 +163,7 @@ indent_size = 2
 indent_size = 2
 
 # Xml files
-[*.{xml,stylecop,resx,ruleset}]
+[*.{xml,stylecop,resx,ruleset,slnx}]
 indent_size = 2
 
 # Xml config files

eng/pipelines/stages/ci-build-extensions-package-stage.yml

@@ -95,6 +95,26 @@ stages:
             -p:BuildNumber=$(Build.BuildNumber)
             -p:ExtensionsPackageVersion=${{parameters.packageVersion}}
 
+        # Explicitly unset the $PLATFORM environment variable that is set by the
+        # 'ADO Build properties' Library in the ADO SqlClientDrivers public
+        # project.  This is defined with a non-standard dotnet platform of
+        # 'AnyCPU', and will fail the builds if left defined.  The Extensions
+        # package does not require any specific dotnet Platform, and so its
+        # solution file doesn't support any non-standard platforms.
+        #
+        # Note that Azure Pipelines will inject this variable as PLATFORM into
+        # the environment of all tasks in this job.
+        #
+        # See: https://learn.microsoft.com/en-us/azure/devops/pipelines/process/variables?view=azure-devops&tabs=yaml%2Cbatch
+        #
+        - name: Platform
+          value: ''
+
+        # Do the same for $CONFIGURATION since we explicitly set it using the
+        # 'buildConfiguration' parameter.
+        - name: Configuration
+          value: ''
+
       steps:
 
       - task: UseDotNet@2