bpo-35433: Properly detect installed SDK versions (GH-11009)

PCbuild/build.bat

@@ -148,4 +148,5 @@ goto :eof
 
 :Version
 rem Display the current build version information
-%MSBUILD% "%dir%python.props" /t:ShowVersionInfo /v:m /nologo %1 %2 %3 %4 %5 %6 %7 %8 %9
+call "%dir%find_msbuild.bat" %MSBUILD%
+if not ERRORLEVEL 1 %MSBUILD% "%dir%pythoncore.vcxproj" /t:ShowVersionInfo /v:m /nologo %1 %2 %3 %4 %5 %6 %7 %8 %9

PCbuild/python.props

@@ -77,14 +77,18 @@
     -->
     <_RegistryVersion>$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v10.0@ProductVersion)</_RegistryVersion>
     <_RegistryVersion Condition="$(_RegistryVersion) == ''">$(Registry:HKEY_LOCAL_MACHINE\WOW6432Node\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v10.0@ProductVersion)</_RegistryVersion>
-    <DefaultWindowsSDKVersion>10.0.17134.0</DefaultWindowsSDKVersion>
-    <DefaultWindowsSDKVersion Condition="$(_RegistryVersion) == '10.0.16299'">10.0.16299.0</DefaultWindowsSDKVersion>
-    <DefaultWindowsSDKVersion Condition="$(_RegistryVersion) == '10.0.15063'">10.0.15063.0</DefaultWindowsSDKVersion>
-    <DefaultWindowsSDKVersion Condition="$(_RegistryVersion) == '10.0.14393'">10.0.14393.0</DefaultWindowsSDKVersion>
-    <DefaultWindowsSDKVersion Condition="$(_RegistryVersion) == '10.0.10586'">10.0.10586.0</DefaultWindowsSDKVersion>
-    <DefaultWindowsSDKVersion Condition="$(_RegistryVersion) == '10.0.10240'">10.0.10240.0</DefaultWindowsSDKVersion>
+    <!-- Sometimes the version in the registry has to .0 suffix, and sometimes it doesn't. Check and add it -->
+    <_RegistryVersion Condition="$(_RegistryVersion) != '' and !$(_RegistryVersion.EndsWith('.0'))">$(_RegistryVersion).0</_RegistryVersion>
+
+    <!-- The minimum allowed SDK version to use for building -->
+    <DefaultWindowsSDKVersion>10.0.10586.0</DefaultWindowsSDKVersion>
+    <DefaultWindowsSDKVersion Condition="$([System.Version]::Parse($(_RegistryVersion))) > $([System.Version]::Parse($(DefaultWindowsSDKVersion)))">$(_RegistryVersion)</DefaultWindowsSDKVersion>
   </PropertyGroup>
   
+  <PropertyGroup Condition="$(WindowsTargetPlatformVersion) == ''">
+    <WindowsTargetPlatformVersion>$(DefaultWindowsSDKVersion)</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(OverrideVersion)' == ''">
     <!--
     Read version information from Include\patchlevel.h. The following properties are set:
@@ -190,5 +194,6 @@
     <Message Importance="high" Text="Field3Value:         $(Field3Value)" />
     <Message Importance="high" Text="SysWinVer:           $(SysWinVer)" />
     <Message Importance="high" Text="PyDllName:           $(PyDllName)" />
+    <Message Importance="high" Text="WindowsSdkVersion:   $(TargetPlatformVersion)" />
   </Target>
 </Project>