diff --git a/windows/msvc/genhdr.targets b/windows/msvc/genhdr.targets
index 3d9a148bed..a2b4c80964 100644
--- a/windows/msvc/genhdr.targets
+++ b/windows/msvc/genhdr.targets
@@ -3,33 +3,74 @@
 
   <Import Project="paths.props" Condition="'$(PyPathsIncluded)' != 'True'"/>
 
-  <!--Generate qstrdefs.h and mpversion.h similar to what is done in py/py.mk-->
-  <Target Name="GenerateHeaders" DependsOnTargets="MakeQstrData;MakeVersionHdr">
+  <!--Generate qstrdefs.h and mpversion.h similar to what is done in py/mkrules.mk-->
+  <Target Name="GenerateHeaders" DependsOnTargets="MakeVersionHdr;MakeQstrData">
   </Target>
 
   <PropertyGroup>
     <DestDir>$(PyBuildDir)genhdr\</DestDir>
     <PySrcDir>$(PyBaseDir)py\</PySrcDir>
+    <QstrDefs>$(PyBaseDir)unix\qstrdefsport.h</QstrDefs>
+    <QstrDefsCollected>$(DestDir)qstrdefscollected.h</QstrDefsCollected>
+    <QstrGen>$(DestDir)qstrdefs.generated.h</QstrGen>
     <PyPython Condition="'$(PyPython)' == ''">python</PyPython>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PyQstrSourceFiles Include="@(ClCompile);$(PySrcDir)qstrdefs.h"/>
+  </ItemGroup>
+
   <Target Name="MakeDestDir">
     <MakeDir Directories="$(DestDir)"/>
   </Target>
 
-  <Target Name="MakeQstrData" DependsOnTargets="MakeDestDir">
-    <PropertyGroup>
-      <PreProc>$(DestDir)qstrdefs.preprocessed.h</PreProc>
-      <QstrDefs>$(PyBaseDir)unix\qstrdefsport.h</QstrDefs>
-      <DestFile>$(DestDir)qstrdefs.generated.h</DestFile>
-      <TmpFile>$(DestFile).tmp</TmpFile>
-    </PropertyGroup>
+  <Target Name="MakeQstrDefs" DependsOnTargets="MakeDestDir" Inputs="@(PyQstrSourceFiles)" Outputs="$(QstrDefsCollected)">
     <ItemGroup>
       <PyIncDirs Include="$(PyIncDirs)"/>
+      <PreProcDefs Include=" %(ClCompile.PreProcessorDefinitions)"/>
+      <PyQstrSourceFiles>
+        <Qstr>$([System.String]::new('%(FullPath)').Replace('$(PyBaseDir)', '$(DestDir)'))</Qstr>
+      </PyQstrSourceFiles>
+      <PyQstrSourceFiles>
+        <Qstr>$([System.IO.Path]::ChangeExtension('%(Qstr)', '.qstr'))</Qstr>
+        <PreProc>$([System.IO.Path]::ChangeExtension('%(Qstr)', '.pp'))</PreProc>
+        <QstrDir>$([System.IO.Path]::GetDirectoryName('%(Qstr)'))</QstrDir>
+        <PreProcOnly>$([System.String]::new('%(FileName)').Contains('qstrdefs'))</PreProcOnly>
+      </PyQstrSourceFiles>
     </ItemGroup>
-    <Exec Command="cl /nologo /I@(PyIncDirs, ' /I') /Fi$(PreProc) /P $(PySrcDir)qstrdefs.h"/>
-    <Exec Command="$(PyPython) $(PySrcDir)makeqstrdata.py $(PreProc) $(QstrDefs) > $(TmpFile)"/>
-    <MSBuild Projects="$(MSBuildThisFileFullPath)" Targets="CopyFileIfDifferent" Properties="SourceFile=$(TmpFile);DestFile=$(DestFile)"/>
+    <PropertyGroup>
+
+    </PropertyGroup>
+
+    <!-- Preprocess and pass to makeqstrdefs if needed, else just copy -->
+    <MakeDir Directories="@(PyQstrSourceFiles->'%(QstrDir)')"/>
+    <Touch Files="$(QstrGen)" AlwaysCreate="true"/>
+
+    <Exec Command="cl /nologo /I@(PyIncDirs, ' /I') /D@(PreProcDefs, ' /D') /Fi%(PyQstrSourceFiles.PreProc) /P %(PyQstrSourceFiles.Identity)"/>
+    <Exec Command="$(PyPython) $(PySrcDir)makeqstrdefs.py -s -o %(PyQstrSourceFiles.Qstr) %(PyQstrSourceFiles.PreProc)" Condition="'%(PyQstrSourceFiles.PreProcOnly)' != 'True'"/>
+    <Copy SourceFiles="%(PyQstrSourceFiles.PreProc)" DestinationFiles="%(PyQstrSourceFiles.Qstr)" Condition="'%(PyQstrSourceFiles.PreProcOnly)' == 'True'"/>
+
+    <!-- Collect all output (where qstrdefs file(s) have priority over autogenerated ones), then
+         filter out lines which definitely aren't qstr definitions so we don't end up with a huge (> 10mb) filesize -->
+    <ReadLinesFromFile File="%(PyQstrSourceFiles.Qstr)" Condition="'%(PyQstrSourceFiles.PreProcOnly)' == 'True'">
+      <Output TaskParameter="Lines" ItemName="PreProcLines"/>
+    </ReadLinesFromFile>
+    <ReadLinesFromFile File="%(PyQstrSourceFiles.Qstr)">
+      <Output TaskParameter="Lines" ItemName="PreProcLines"/>
+    </ReadLinesFromFile>
+    <ItemGroup>
+      <QStrLines Include="@(PreProcLines)" Condition="$([System.String]::new('%(Identity)').Contains('Q'))"/>
+    </ItemGroup>
+
+    <WriteLinesToFile Lines="@(QStrLines)" File="$(QstrDefsCollected)" Overwrite="true"/>
+  </Target>
+
+  <Target Name="MakeQstrData" DependsOnTargets="MakeQstrDefs">
+    <PropertyGroup>
+      <TmpFile>$(DestFile).tmp</TmpFile>
+    </PropertyGroup>
+    <Exec Command="$(PyPython) $(PySrcDir)makeqstrdata.py $(QstrDefs) $(QstrDefsCollected) > $(TmpFile)"/>
+    <MSBuild Projects="$(MSBuildThisFileFullPath)" Targets="CopyFileIfDifferent" Properties="SourceFile=$(TmpFile);DestFile=$(QstrGen)"/>
   </Target>
 
   <Target Name="MakeVersionHdr" DependsOnTargets="MakeDestDir">