Set the AdditionalManifestFiles as a property sheet

This is the (better) way. See, Deuce knows the coolness of property sheets!

src/conio/conio_gdi.props

@@ -14,6 +14,9 @@
       <AdditionalDependencies>winmm.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <SubSystem>Windows</SubSystem>
     </Link>
+    <Manifest>
+      <AdditionalManifestFiles>$(MSBuildThisFileDirectory)ciolib.manifest</AdditionalManifestFiles>
+    </Manifest>
   </ItemDefinitionGroup>
   <ItemGroup />
-</Project>
+</Project>
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