Use WIX_NATIVE_MACHINE to detect native architecture of target machine

src/redist/targets/packaging/windows/clisdk/bundle.wxs

@@ -20,7 +20,7 @@
 
     <!-- Permit same path on non-ARM64 machines since past SDKs always wrote this value -->
     <bal:Condition Message="The installation path for ARM64 SDK installations: &quot;[DOTNETHOME_ARM64]&quot; cannot be the same as for x64 SDK installations: &quot;[DOTNETHOME_X64]&quot;">
-        WixBundleInstalled OR (NOT DOTNETHOME_ARM64 ~= DOTNETHOME_X64) OR (NOT NativeProcessorArchitecture=&quot;ARM64&quot;) OR DOTNETHOMESIMILARITYCHECKOVERRIDE
+        WixBundleInstalled OR (NOT DOTNETHOME_ARM64 ~= DOTNETHOME_X64) OR (NOT NativeMachine=&quot;$(var.NativeMachine_arm64)&quot;) OR DOTNETHOMESIMILARITYCHECKOVERRIDE
     </bal:Condition>
 
     <BootstrapperApplicationRef Id="WixStandardBootstrapperApplication.Foundation">
@@ -77,20 +77,11 @@
               Key="SOFTWARE\dotnet\Setup\InstalledVersions\x64"
               Value="InstallLocation" />
 
-    <!-- Determine native OS architecture -->
-    <util:RegistrySearch Id="CheckProcessorArchitecture_x64"
-              After="DotnetInstallLocation_x64"
-              Variable="NativeProcessorArchitecture"
-              Result="value"
-              Root="HKLM"
-              Key="SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
-              Value="PROCESSOR_ARCHITECTURE" />
-
     <!-- Check default location when on x64 OS-->
     <util:FileSearch Id="DotnetExeSearch_x64"
-              After="CheckProcessorArchitecture_x64"
+              After="DotnetInstallLocation_x64"
               Variable="DotnetExeExists_x64"
-              Condition="NOT DotnetInstallLocationExists_x64 AND NativeProcessorArchitecture=&quot;AMD64&quot;"
+              Condition="NOT DotnetInstallLocationExists_x64 AND (NOT NativeMachine OR NativeMachine=&quot;$(var.NativeMachine_x64)&quot;)"
               Result="exists"
               Path="[ProgramFiles64Folder]dotnet\dotnet.exe"/>
     <util:DirectorySearch Id="DotnetExeLocation_x64"
@@ -101,9 +92,9 @@
 
     <!-- Check alternate location on non-x64 OS -->
     <util:FileSearch Id="DotnetExeSearch_alt_x64"
-              After="CheckProcessorArchitecture_x64"
+              After="DotnetInstallLocation_x64"
               Variable="DotnetExeExists_alt_x64"
-              Condition="NOT DotnetInstallLocationExists_x64 AND NOT NativeProcessorArchitecture=&quot;AMD64&quot;"
+              Condition="NOT DotnetInstallLocationExists_x64 AND NOT NativeMachine=&quot;$(var.NativeMachine_x64)&quot;"
               Result="exists"
               Path="[ProgramFiles64Folder]dotnet\x64\dotnet.exe"/>
     <util:DirectorySearch Id="DotnetExeLocation_alt_x64"

src/redist/targets/packaging/windows/clisdk/dotnethome_x64.wxs

@@ -5,23 +5,27 @@
     <?define Platform = "$(sys.BUILDARCH)"?>
   <?endif?>
 
-  <!-- InstallerArchitecture matches the expected values for PROCESSOR_ARCHITECTURE 
+  <!-- InstallerNativeMachine matches the expected values for image file machine constants
-       https://docs.microsoft.com/en-us/windows/win32/winprog64/wow64-implementation-details  -->
+       https://docs.microsoft.com/en-us/windows/win32/sysinfo/image-file-machine-constants -->
   <?if $(var.Platform)~=x86?>
-    <?define InstallerArchitecture="X86"?>
+    <?define InstallerNativeMachine=332?>
   <?elseif $(var.Platform)~=x64?>
-    <?define InstallerArchitecture="AMD64"?>
+    <?define InstallerNativeMachine=34404?>
   <?elseif $(var.Platform)~=arm64?>
-    <?define InstallerArchitecture="ARM64"?>
+    <?define InstallerNativeMachine=43620?>
   <?else?>
-    <?error Unknown platform, $(var.Platform) ?>?
+    <?error Unknown platform, $(var.Platform) ?>
   <?endif?>
 
   <Fragment>
-    <!-- Identify when installing in emulation as when PROCESSOR_ARCHITECTURE does not match the installer architecture
+    <!-- Identify when installing in emulation as when WIX_NATIVE_MACHINE does not match the installer
-          https://docs.microsoft.com/en-us/windows/win32/winprog64/wow64-implementation-details -->
+         native machine (where supported).  Also detect running under WOW on x86 using VersionNT64,
+         since WIX_NATIVE_MACHINE cannot be retrieved on older Windows builds. -->
     <SetProperty Action="Set_NON_NATIVE_ARCHITECTURE" Id="NON_NATIVE_ARCHITECTURE" Value="true" Before="CostFinalize">
-      NOT %PROCESSOR_ARCHITECTURE="$(var.InstallerArchitecture)"
+     <?if $(var.Platform)~=x86?>
+      VersionNT64 OR
+     <?endif?>
+      WIX_NATIVE_MACHINE AND NOT WIX_NATIVE_MACHINE="$(var.InstallerNativeMachine)"
     </SetProperty>
   </Fragment>
 

src/redist/targets/packaging/windows/clisdk/variables.wxi

@@ -15,7 +15,14 @@
   <?define LCID  = "$(var.ProductLanguage)"?>
   <?define DowngradeErrorMessage  = "A newer version is already installed; please uninstall it and re-run setup."?>
 
+  <!-- NativeMachine values match the expected values for image file machine constants
+       https://docs.microsoft.com/en-us/windows/win32/sysinfo/image-file-machine-constants -->
+  <?define NativeMachine_x86=332?>
+  <?define NativeMachine_x64=34404?>
+  <?define NativeMachine_arm64=43620?>
+  
   <?define Platform   =   "$(sys.BUILDARCH)" ?>
+  
   <?if $(var.Platform)=x86?>
   <?define PlatformToken="X86"?>
   <?define WixQuietExec="WixQuietExec"?>