[msbuild] fix integration caching (microsoft#16787)

we would always run on build, as opposed to only running when changes happened

scripts/buildsystems/msbuild/vcpkg.targets

@@ -73,31 +73,41 @@
              Importance="High" Condition="'$(VcpkgEnabled)' == 'true' and '$(VcpkgNormalizedConfiguration)' == ''"/>
   </Target>
 
-  <ItemGroup>
-    <_ZVcpkgInstallManifestDependenciesInputs Include="$(VcpkgManifestRoot)vcpkg.json"/>
-    <_ZVcpkgInstallManifestDependenciesInputs Include="$(VcpkgManifestRoot)vcpkg-configuration.json" Condition="Exists('$(VcpkgManifestRoot)vcpkg-configuration.json')"/>
+  <PropertyGroup Condition="'$(VcpkgEnabled)' == 'true'">
+    <_ZVcpkgManifestFileLocation>$(VcpkgManifestRoot)vcpkg.json </_ZVcpkgManifestFileLocation>
+    <_ZVcpkgConfigurationFileLocation>$(VcpkgManifestRoot)vcpkg-configuration.json</_ZVcpkgConfigurationFileLocation>
+
+    <_ZVcpkgTLogFileLocation>$(TLogLocation)VcpkgInstallManifest$(VcpkgTriplet).$(VcpkgHostTriplet).read.1u.tlog</_ZVcpkgTLogFileLocation>
+    <_ZVcpkgMSBuildStampFile>$(VcpkgInstalledDir).msbuildstamp-$(VcpkgTriplet).$(VcpkgHostTriplet).stamp</_ZVcpkgMSBuildStampFile>
+  </PropertyGroup>
+  <ItemGroup Condition="'$(VcpkgEnabled)' == 'true'">
+    <_ZVcpkgInstallManifestDependenciesInputs Include="$(_ZVcpkgManifestFileLocation)"/>
+    <_ZVcpkgInstallManifestDependenciesInputs Include="$(_ZVcpkgConfigurationFileLocation)" Condition="Exists('$(_ZVcpkgConfigurationFileLocation)')"/>
+
+    <_ZVcpkgInstallManifestDependenciesOutputs Include="$(_ZVcpkgTLogFileLocation)"/>
+    <_ZVcpkgInstallManifestDependenciesOutputs Include="$(_ZVcpkgMSBuildStampFile)"/>
   </ItemGroup>
 
   <Target Name="VcpkgInstallManifestDependencies" BeforeTargets="ClCompile"
           Condition="'$(VcpkgEnabled)' == 'true' and '$(VcpkgEnableManifest)' == 'true' and '$(VcpkgManifestInstall)' == 'true'"
           Inputs="@(_ZVcpkgInstallManifestDependenciesInputs)"
-          Outputs="$(TLogLocation)VcpkgInstallManifest$(VcpkgTriplet).read.1u.tlog;$(VcpkgInstalledDir).msbuildstamp-$(VcpkgTriplet).$(VcpkgHostTriplet).stamp">
+          Outputs="@(_ZVcpkgInstallManifestDependenciesOutputs)">
     <Message Text="Installing vcpkg dependencies to $(VcpkgInstalledDir)" Importance="High" />
     <MakeDir Directories="$(TLogLocation)" />
     <ItemGroup>
-      <_VcpkgItemToDelete Include="$(TLogLocation)VcpkgInstallManifest*.read.1u.tlog" />
-      <_VcpkgItemToDelete Include="$(VcpkgInstalledDir).msbuildstamp-*" />
+      <_ZVcpkgItemToDelete Include="$(TLogLocation)VcpkgInstallManifest*.read.1u.tlog" />
+      <_ZVcpkgItemToDelete Include="$(VcpkgInstalledDir).msbuildstamp-*" />
     </ItemGroup>
-    <Delete Files="@(_VcpkgItemToDelete)" />
+    <Delete Files="@(_ZVcpkgItemToDelete)" />
     <Message Text="%22$(_ZVcpkgExecutable)%22 install $(_ZVcpkgHostTripletParameter) --x-wait-for-lock --triplet %22$(VcpkgTriplet)%22 --vcpkg-root %22$(VcpkgRoot)\%22 %22--x-manifest-root=$(VcpkgManifestRoot)\%22 %22--x-install-root=$(VcpkgInstalledDir)\%22 $(VcpkgAdditionalInstallOptions)"
           Importance="High" />
     <Exec Command="%22$(_ZVcpkgExecutable)%22 install $(_ZVcpkgHostTripletParameter) --x-wait-for-lock --triplet %22$(VcpkgTriplet)%22 --vcpkg-root %22$(VcpkgRoot)\%22 %22--x-manifest-root=$(VcpkgManifestRoot)\%22 %22--x-install-root=$(VcpkgInstalledDir)\%22 $(VcpkgAdditionalInstallOptions)"
           StandardOutputImportance="High" />
-    <WriteLinesToFile File="$(TLogLocation)VcpkgInstallManifest$(VcpkgTriplet).$(VcpkgHostTriplet).read.1u.tlog"
+    <WriteLinesToFile File="$(_ZVcpkgTLogFileLocation)"
                       Lines="@(_VcpkgInstallManifestDependenciesInputs -> '^%(Identity)')"
                       Encoding="Unicode"
                       Overwrite="true"/>
-    <Touch Files="$(VcpkgInstalledDir).msbuildstamp-$(VcpkgTriplet).$(VcpkgHostTriplet).stamp" AlwaysCreate="true" />
+    <Touch Files="$(_ZVcpkgMSBuildStampFile)" AlwaysCreate="true" />
 
     <CreateProperty Value="false">
       <Output TaskParameter="ValueSetByTask" PropertyName="Link_MinimalRebuildFromTracking" />