diff --git a/build/csrihelper/csrihelper.vcxproj b/build/csrihelper/csrihelper.vcxproj
index a20476d83..c4115f23b 100644
--- a/build/csrihelper/csrihelper.vcxproj
+++ b/build/csrihelper/csrihelper.vcxproj
@@ -10,7 +10,6 @@
   <PropertyGroup Label="AegisubConfiguration">
     <AegisubProjectType>lib</AegisubProjectType>
     <SrcDir>..\..\vendor\csri\</SrcDir>
-    <HeaderRoot>$(SrcDir)include</HeaderRoot>
   </PropertyGroup>
   <ImportGroup Label="PropertySheets">
     <Import Project="$(MSBuildThisFileDirectory)..\aegisub.props" />
@@ -22,6 +21,9 @@
       <PreprocessorDefinitions>CSRI_NO_EXPORT;_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(SrcDir)include\;$(SrcDir)lib\;$(SrcDir)lib\win32\;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(SrcDir)include</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
diff --git a/build/expat/expat.vcxproj b/build/expat/expat.vcxproj
index 1745e183d..399d6ec12 100644
--- a/build/expat/expat.vcxproj
+++ b/build/expat/expat.vcxproj
@@ -9,7 +9,6 @@
   <PropertyGroup Label="AegisubConfiguration">
     <AegisubProjectType>lib</AegisubProjectType>
     <SrcDir>..\..\vendor\wxWidgets\src\expat\lib</SrcDir>
-    <HeaderRoot>$(SrcDir)</HeaderRoot>
   </PropertyGroup>
   <ImportGroup Label="PropertySheets">
     <Import Project="$(MSBuildThisFileDirectory)..\aegisub.props" />
@@ -20,6 +19,9 @@
     <ClCompile>
       <PreprocessorDefinitions>COMPILED_FROM_DSP;%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(SrcDir)</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
diff --git a/build/ffmpeg/ffmpeg.vcxproj b/build/ffmpeg/ffmpeg.vcxproj
index 9120ef8fe..a0ef8a80a 100644
--- a/build/ffmpeg/ffmpeg.vcxproj
+++ b/build/ffmpeg/ffmpeg.vcxproj
@@ -11,9 +11,6 @@
   <ImportGroup Label="PropertySheets">
     <Import Project="$(MSBuildThisFileDirectory)..\aegisub.props" />
   </ImportGroup>
-  <PropertyGroup>
-    <HeaderRoot>$(FfmpegSrcDir)</HeaderRoot>
-  </PropertyGroup>
 
   <!-- Project specific configuration -->
   <ItemDefinitionGroup>
@@ -54,6 +51,9 @@
       <WholeProgramOptimization>false</WholeProgramOptimization>
       <InputRelativeSourceDir>$(FfmpegSrcDir)</InputRelativeSourceDir>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(FfmpegSrcDir)</HeaderRoot>
+    </InstallHeader>
     <Yasm>
       <InputRelativeSourceDir>$(FfmpegSrcDir)\</InputRelativeSourceDir>
     </Yasm>
@@ -1073,9 +1073,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <InstallHeaderTo Include="$(MSBuildThisFileDirectory)\libavutil\avconfig.h">
-      <Destination>libavutil\</Destination>
-    </InstallHeaderTo>
+    <InstallHeader Include="$(MSBuildThisFileDirectory)\libavutil\avconfig.h">
+      <HeaderRoot>$(MSBuildThisFileDirectory)</HeaderRoot>
+    </InstallHeader>
 
     <InstallHeader Include="$(FfmpegSrcDir)\libavcodec\audiodsp.h" />
     <InstallHeader Include="$(FfmpegSrcDir)\libavcodec\avcodec.h" />
diff --git a/build/ffms2/ffms2.vcxproj b/build/ffms2/ffms2.vcxproj
index cc27cb8d5..ad574ed25 100644
--- a/build/ffms2/ffms2.vcxproj
+++ b/build/ffms2/ffms2.vcxproj
@@ -16,7 +16,6 @@
 
   <PropertyGroup>
     <Ffms2PreprocessorHaalisource Condition="'$(Ffms2UseAtl)'!='0'">HAALISOURCE;</Ffms2PreprocessorHaalisource>
-    <HeaderRoot>$(FfmsSrcDir)\include</HeaderRoot>
   </PropertyGroup>
 
   <!-- Project specific configuration -->
@@ -42,6 +41,9 @@
     <Link>
       <AdditionalLibraryDirectories>$(AegisubLibraryDir);%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
     </Link>
+    <InstallHeader>
+      <HeaderRoot>$(FfmsSrcDir)\include</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
diff --git a/build/fftw/fftw.vcxproj b/build/fftw/fftw.vcxproj
index c38dd20cd..d33267b42 100644
--- a/build/fftw/fftw.vcxproj
+++ b/build/fftw/fftw.vcxproj
@@ -15,9 +15,6 @@
   </ImportGroup>
 
   <!-- Project specific configuration -->
-  <PropertyGroup>
-    <HeaderRoot>$(FftwSrcDir)\api</HeaderRoot>
-  </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>
@@ -41,6 +38,9 @@
       <StructMemberAlignment>Default</StructMemberAlignment>
       <InputRelativeSourceDir>$(FftwSrcDir)</InputRelativeSourceDir>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(FftwSrcDir)\api</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
diff --git a/build/fontconfig/fontconfig.vcxproj b/build/fontconfig/fontconfig.vcxproj
index 1576ab579..6368090bc 100644
--- a/build/fontconfig/fontconfig.vcxproj
+++ b/build/fontconfig/fontconfig.vcxproj
@@ -15,9 +15,6 @@
   </ImportGroup>
 
   <!-- Project specific configuration -->
-  <PropertyGroup>
-    <HeaderRoot>$(FontconfigSrcDir)</HeaderRoot>
-  </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>
@@ -30,6 +27,9 @@
         %(PreprocessorDefinitions)
       </PreprocessorDefinitions>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(FontconfigSrcDir)</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Project References -->
diff --git a/build/freetype2/freetype.vcxproj b/build/freetype2/freetype.vcxproj
index f4761d8f1..69ec78e4c 100644
--- a/build/freetype2/freetype.vcxproj
+++ b/build/freetype2/freetype.vcxproj
@@ -15,9 +15,6 @@
   </ImportGroup>
 
   <!-- Project specific configuration -->
-  <PropertyGroup>
-    <HeaderRoot>$(Freetype2SrcDir)\include</HeaderRoot>
-  </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>$(Freetype2SrcDir)\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
@@ -29,6 +26,9 @@
     <ResourceCompile>
       <Culture>0x0409</Culture>
     </ResourceCompile>
+    <InstallHeader>
+      <HeaderRoot>$(Freetype2SrcDir)\include</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
diff --git a/build/fribidi/fribidi.vcxproj b/build/fribidi/fribidi.vcxproj
index a02a22fd3..aa1533f1b 100644
--- a/build/fribidi/fribidi.vcxproj
+++ b/build/fribidi/fribidi.vcxproj
@@ -54,8 +54,11 @@
     <ClCompile Include="$(FribidiSrcDir)\lib\fribidi-run.c" />
     <ClCompile Include="$(FribidiSrcDir)\lib\fribidi-shape.c" />
     <ClCompile Include="$(FribidiSrcDir)\lib\fribidi.c" />
-    <InstallHeaderTo Include="$(FribidiSrcDir)\lib\*.h;$(MSBuildThisFileDirectory)fribidi-config.h">
-      <Destination>fribidi\</Destination>
-    </InstallHeaderTo>
+    <InstallHeader Include="$(FribidiSrcDir)\lib\*.h">
+      <HeaderRoot>$(FribidiSrcDir)\lib</HeaderRoot>
+    </InstallHeader>
+    <InstallHeader Include="$(MSBuildThisFileDirectory)fribidi-config.h">
+      <HeaderRoot>$(MSBuildThisFileDirectory)</HeaderRoot>
+    </InstallHeader>
   </ItemGroup>
 </Project>
diff --git a/build/icu/icu.vcxproj b/build/icu/icu.vcxproj
index 9e96e44d7..602b7e3e9 100644
--- a/build/icu/icu.vcxproj
+++ b/build/icu/icu.vcxproj
@@ -76,6 +76,14 @@
   </Target>
 
   <!-- Source files -->
+  <ItemGroup>
+    <InstallHeader Include="$(IcuSrcDir)\i18n\unicode\*.h">
+      <HeaderRoot>$(IcuSrcDir)\i18n</HeaderRoot>
+    </InstallHeader>
+    <InstallHeader Include="$(IcuSrcDir)\common\unicode\*.h">
+      <HeaderRoot>$(IcuSrcDir)\common</HeaderRoot>
+    </InstallHeader>
+  </ItemGroup>
   <ItemGroup>
     <ClCompile Include="$(AegisubObjectDir)\$(IcuDt).c" />
     <ClCompile Include="$(IcuSrcDir)\common\ubidi.c" />
@@ -364,9 +372,6 @@
     <ClInclude Include="$(IcuSrcDir)\common\uvectr32.h" />
     <ClInclude Include="$(IcuSrcDir)\common\uvectr64.h" />
     <ClInclude Include="$(IcuSrcDir)\common\wintz.h" />
-    <InstallHeaderTo Include="$(IcuSrcDir)\common\unicode\*.h">
-      <Destination>unicode\</Destination>
-    </InstallHeaderTo>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="$(IcuSrcDir)\i18n\filteredbrk.cpp" />
@@ -689,9 +694,6 @@
     <ClInclude Include="$(IcuSrcDir)\i18n\uspoof_conf.h" />
     <ClInclude Include="$(IcuSrcDir)\i18n\uspoof_impl.h" />
     <ClInclude Include="$(IcuSrcDir)\i18n\uspoof_wsconf.h" />
-    <InstallHeaderTo Include="$(IcuSrcDir)\i18n\unicode\*.h">
-      <Destination>unicode\</Destination>
-    </InstallHeaderTo>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\luajit-minilua\luajit-minilua.vcxproj">
diff --git a/build/install.targets b/build/install.targets
index 077227549..b43e8f7cd 100644
--- a/build/install.targets
+++ b/build/install.targets
@@ -1,27 +1,42 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+  <ItemDefinitionGroup>
+    <InstallHeader>
+      <Destination></Destination>
+    </InstallHeader>
+  </ItemDefinitionGroup>
+  
+  <Target
+    Name="ComputeHeaderOutputs"
+    Inputs="@(InstallHeader)"
+    Outputs="@(InstallHeader->'%(HeaderRoot)|%(RelativeDir)')"
+    BeforeTargets="InstallHeaders"
+    >
+    <CalculateOutputDir
+      Items="@(InstallHeader)"
+      SourceDir="%(HeaderRoot)"
+      DestinationDir="$(AegisubSourceBase)include"
+      >
+      <Output ItemName="_InstallHeader" TaskParameter="Outputs" />
+    </CalculateOutputDir>
+  </Target>
+  
   <Target
     Name="InstallHeaders"
     BeforeTargets="ClCompile"
-    Inputs="@(InstallHeader)"
-    Outputs="@(InstallHeader->Replace($(HeaderRoot), $(AegisubSourceBase)include))"
+    Inputs="@(_InstallHeader)"
+    Outputs="@(_InstallHeader->'%(OutputDir)%(Destination)%(Filename)%(Extension)')"
     >
+    <Error
+      Condition="'%(_InstallHeader.OutputDir)' == ''"
+      Text="OutputDir for _InstallHeader item is blank, problem during ComputeHeaderOutputs target?"
+      />
     <Copy
-      SourceFiles="@(InstallHeader)"
-      DestinationFiles="@(InstallHeader->Replace($(HeaderRoot), $(AegisubSourceBase)include))"
-      SkipUnchangedFiles="true"
-      />
-  </Target>
-  <Target
-    Name="InstallHeadersTo"
-    BeforeTargets="ClCompile"
-    Inputs="@(InstallHeaderTo)"
-    Outputs="@(InstallHeaderTo -> '$(AegisubSourceBase)include\%(Destination)%(Filename)%(Extension)')"
-    >
-    <Copy
-      SourceFiles="@(InstallHeaderTo)"
-      DestinationFiles="@(InstallHeaderTo -> '$(AegisubSourceBase)include\%(Destination)%(Filename)%(Extension)')"
+      SourceFiles="@(_InstallHeader)"
+      DestinationFiles="@(_InstallHeader->'%(OutputDir)%(Destination)%(Filename)%(Extension)')"
       SkipUnchangedFiles="true"
       />
   </Target>
+  
 </Project>
diff --git a/build/libass/libass.vcxproj b/build/libass/libass.vcxproj
index bd13bf3cd..e8dc49a3e 100644
--- a/build/libass/libass.vcxproj
+++ b/build/libass/libass.vcxproj
@@ -29,15 +29,16 @@
         %(PreprocessorDefinitions)
       </PreprocessorDefinitions>
     </ClCompile>
-    <InstallHeaderTo>
+    <InstallHeader>
+      <HeaderRoot>$(LibassSrcDir)\libass</HeaderRoot>
       <Destination>ass\</Destination>
-    </InstallHeaderTo>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
   <ItemGroup>
-    <InstallHeaderTo Include="$(LibassSrcDir)\libass\ass.h" />
-    <InstallHeaderTo Include="$(LibassSrcDir)\libass\ass_types.h" />
+    <InstallHeader Include="$(LibassSrcDir)\libass\ass.h" />
+    <InstallHeader Include="$(LibassSrcDir)\libass\ass_types.h" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="$(LibassSrcDir)\libass\ass.h" />
diff --git a/build/libiconv/libiconv.vcxproj b/build/libiconv/libiconv.vcxproj
index 9412a0bfe..712551531 100644
--- a/build/libiconv/libiconv.vcxproj
+++ b/build/libiconv/libiconv.vcxproj
@@ -15,15 +15,15 @@
   </ImportGroup>
 
   <!-- Project specific configuration -->
-  <PropertyGroup>
-    <HeaderRoot>$(SrcDir)\include</HeaderRoot>
-  </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>$(SrcDir)include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <CompileAs>CompileAsC</CompileAs>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(SrcDir)include</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- Source files -->
diff --git a/build/libpng/libpng.vcxproj b/build/libpng/libpng.vcxproj
index 0f928dd18..9d57ff478 100644
--- a/build/libpng/libpng.vcxproj
+++ b/build/libpng/libpng.vcxproj
@@ -9,7 +9,6 @@
   <PropertyGroup Label="AegisubConfiguration">
     <AegisubProjectType>lib</AegisubProjectType>
     <SrcDir>..\..\vendor\wxWidgets\src\png\</SrcDir>
-    <HeaderRoot>$(SrcDir)</HeaderRoot>
   </PropertyGroup>
   <ImportGroup Label="PropertySheets">
     <Import Project="$(MSBuildThisFileDirectory)..\aegisub.props" />
@@ -21,6 +20,12 @@
       <Project>{10f22a5a-dd9e-44a1-ba2e-2a9a7c78b0ee}</Project>
     </ProjectReference>
   </ItemGroup>
+  
+  <ItemDefinitionGroup>
+    <InstallHeader>
+      <HeaderRoot>$(SrcDir)</HeaderRoot>
+    </InstallHeader>
+  </ItemDefinitionGroup>
 
   <!-- Source files -->
   <ItemGroup>
diff --git a/build/luajit/luajit.vcxproj b/build/luajit/luajit.vcxproj
index a144b4c70..58a34500d 100644
--- a/build/luajit/luajit.vcxproj
+++ b/build/luajit/luajit.vcxproj
@@ -15,9 +15,6 @@
   </ImportGroup>
 
   <!-- Project specific configuration -->
-  <PropertyGroup>
-    <HeaderRoot>$(SrcDir)\include</HeaderRoot>
-  </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
       <PreprocessorDefinitions>
@@ -27,6 +24,9 @@
       </PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(AegisubObjectDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(SrcDir)include</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <!-- BuildVM stuff -->
diff --git a/build/tasks.props b/build/tasks.props
index ab77c6a0d..39c594f90 100644
--- a/build/tasks.props
+++ b/build/tasks.props
@@ -5,5 +5,31 @@
   </PropertyGroup>
 
   <UsingTask TaskName="GitVersion" AssemblyFile="$(AegisubBinaryDir)BuildTasks.dll" />
+
+  <UsingTask TaskName="CalculateOutputDir" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll" >
+    <ParameterGroup>
+      <Items ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
+      <SourceDir Required="true" />
+      <DestinationDir Required="true" />
+      <Outputs ParameterType="Microsoft.Build.Framework.ITaskItem[]" Output="true" />
+    </ParameterGroup>
+    <Task>
+      <Code Type="Fragment" Language="cs"><![CDATA[
+        Outputs = new TaskItem[Items.Length];
+        char[] backslash = new char[] {'\\'};
+        var srcdir = SourceDir.Replace('/', '\\').TrimEnd(backslash) + "\\";
+        var dstdir = DestinationDir.Replace('/', '\\').TrimEnd(backslash) + "\\";
+        int i = 0;
+        foreach (var item in Items) {
+          var itemDir = item.GetMetadata("RelativeDir"); // the dir specified in the item Include= attribute
+          var outputDir = itemDir.Replace(srcdir, dstdir).Replace('/', '\\').TrimEnd(backslash) + "\\";
+          var output = new TaskItem(item);
+          ((ITaskItem2)output).SetMetadataValueLiteral("OutputDir", outputDir);
+          Outputs[i] = output;
+          i++;
+        }
+      ]]></Code>
+    </Task>
+  </UsingTask>
 </Project>
 
diff --git a/build/wx/wxWidgets.vcxproj b/build/wx/wxWidgets.vcxproj
index e0903bd8a..2da8d8989 100644
--- a/build/wx/wxWidgets.vcxproj
+++ b/build/wx/wxWidgets.vcxproj
@@ -9,7 +9,6 @@
   <PropertyGroup Label="AegisubConfiguration">
     <AegisubProjectType>lib</AegisubProjectType>
     <SrcDir>..\..\vendor\wxWidgets\</SrcDir>
-    <HeaderRoot>$(SrcDir)include</HeaderRoot>
   </PropertyGroup>
   <ImportGroup Label="PropertySheets">
     <Import Project="$(MSBuildThisFileDirectory)..\aegisub.props" />
@@ -23,6 +22,9 @@
       <PrecompiledHeader>Use</PrecompiledHeader>
       <PrecompiledHeaderFile>wx/wxprec.h</PrecompiledHeaderFile>
     </ClCompile>
+    <InstallHeader>
+      <HeaderRoot>$(SrcDir)include</HeaderRoot>
+    </InstallHeader>
   </ItemDefinitionGroup>
 
   <Target Name="InstallSetup"
diff --git a/build/zlib/zlib.vcxproj b/build/zlib/zlib.vcxproj
index 06e60a16a..1dbf4345d 100644
--- a/build/zlib/zlib.vcxproj
+++ b/build/zlib/zlib.vcxproj
@@ -20,8 +20,12 @@
 
   <!-- Source files -->
   <ItemGroup>
-    <InstallHeaderTo Include="$(ZlibSrcDir)\zlib.h" />
-    <InstallHeaderTo Include="$(MSBuildThisFileDirectory)\zconf.h" />
+    <InstallHeader Include="$(ZlibSrcDir)\zlib.h">
+      <HeaderRoot>$(ZlibSrcDir)</HeaderRoot>
+    </InstallHeader>
+    <InstallHeader Include="$(MSBuildThisFileDirectory)\zconf.h">
+      <HeaderRoot>$(MSBuildThisFileDirectory)</HeaderRoot>
+    </InstallHeader>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="$(ZlibSrcDir)\adler32.c" />