eng/SourceBuild.props: when unset, let the repo determine RuntimeOS. (#82546)

* eng/SourceBuild.props: when unset, let the repo determine RuntimeOS.

When source-build builds runtime, it will pass RuntimeOS and BaseOS.

When the repo is built directly using './build.sh --sb', let the repo
determine those values rather than calculating them in SourceBuild.props.

* global-build-job.yml: remove unneeded runtimeOS param.

Author: tmds

eng/SourceBuild.props

@@ -15,13 +15,6 @@
     <_targetRidPlatformIndex>$(TargetRid.LastIndexOf('-'))</_targetRidPlatformIndex>
     <TargetArch>$(TargetRid.Substring($(_targetRidPlatformIndex)).TrimStart('-'))</TargetArch>
 
-    <!-- RuntimeOS is the build host rid OS. -->
-    <RuntimeOS>$(TargetRid.Substring(0, $(_targetRidPlatformIndex)))</RuntimeOS>
-
-    <!-- BaseOS is an expected known rid in the graph that TargetRid is compatible with.
-         It's used to add TargetRid in the graph if the parent can't be detected. -->
-    <BaseOS>$(RuntimeOS)</BaseOS>
-
     <LogVerbosity Condition="'$(LogVerbosity)' == ''">minimal</LogVerbosity>
   </PropertyGroup>
 
@@ -38,10 +31,13 @@
       <InnerBuildArgs>$(InnerBuildArgs) --nodereuse false</InnerBuildArgs>
       <InnerBuildArgs>$(InnerBuildArgs) --warnAsError false</InnerBuildArgs>
       <InnerBuildArgs>$(InnerBuildArgs) --outputrid $(TargetRid)</InnerBuildArgs>
+      <!-- RuntimeOS is the build host rid OS. -->
       <InnerBuildArgs>$(InnerBuildArgs) /p:RuntimeOS=$(RuntimeOS)</InnerBuildArgs>
+      <!-- BaseOS is an expected known rid in the graph that TargetRid is compatible with.
+         It's used to add TargetRid in the graph if the parent can't be detected. -->
+      <InnerBuildArgs>$(InnerBuildArgs) /p:AdditionalRuntimeIdentifierParent=$(BaseOS)</InnerBuildArgs>
       <InnerBuildArgs Condition="'$(OfficialBuildId)' != ''">$(InnerBuildArgs) /p:OfficialBuildId=$(OfficialBuildId)</InnerBuildArgs>
       <InnerBuildArgs Condition="'$(ContinuousIntegrationBuild)' != ''">$(InnerBuildArgs) /p:ContinuousIntegrationBuild=$(ContinuousIntegrationBuild)</InnerBuildArgs>
-      <InnerBuildArgs>$(InnerBuildArgs) /p:AdditionalRuntimeIdentifierParent=$(BaseOS)</InnerBuildArgs>
       <InnerBuildArgs Condition="'$(SourceBuildUseMonoRuntime)' == 'true'">$(InnerBuildArgs) /p:PrimaryRuntimeFlavor=Mono /p:RuntimeFlavor=Mono</InnerBuildArgs>
     </PropertyGroup>
   </Target>

eng/pipelines/common/global-build-job.yml

@@ -163,7 +163,6 @@ jobs:
             buildScript: $(Build.SourcesDirectory)$(dir)build$(scriptExt)
             nonPortable: ${{ parameters.isNonPortableSourceBuild }}
             targetRID: ${{ parameters.targetRid }}
-            runtimeOS: linux
             name: ${{ parameters.platform }}
 
     - ${{ if in(parameters.osGroup, 'osx', 'maccatalyst', 'ios', 'iossimulator', 'tvos', 'tvossimulator') }}: