fix resolution on HiDPI displays under Windows

The same Windows functionality as scaling user interface elements,
confuses fullscreen games unless they set a particular of metadata to
indicate that they perform the scaling by themselves.

What happened was treating 2160p as 1440p despite the former being
chosen. The same occured with other game title prior to introducing the
metadata bits.

Fortunately with CMake there's no need to invoke the mt.exe "manifest
tool" manually.

Note that the setting of "per-monitor DPI aware" still leaves openmw
confused, hence the choice of global-DPI-aware.

CHANGELOG.md

@@ -1,6 +1,7 @@
 0.46.0
 ------
 
+    Bug #3623: Fix HiDPI on Windows
     Feature #2229: Improve pathfinding AI
     Feature #3442: Default values for fallbacks from ini file
     Task #4686: Upgrade media decoder to a more current FFmpeg API

apps/openmw/CMakeLists.txt

@@ -4,6 +4,7 @@ set(GAME
     engine.cpp
 
     ${CMAKE_SOURCE_DIR}/files/windows/openmw.rc
+    ${CMAKE_SOURCE_DIR}/files/windows/openmw.exe.manifest
 )
 
 if (ANDROID)

files/windows/openmw.exe.manifest

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+    <assemblyIdentity type="win32" name="openmw" version="1.0.0.0"/>
+    <description>Q2PRO</description>
+    <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
+        <security>
+            <requestedPrivileges>
+                <requestedExecutionLevel level="asInvoker" uiAccess="false"/>
+            </requestedPrivileges>
+        </security>
+    </trustInfo>
+    <application xmlns="urn:schemas-microsoft-com:asm.v3">
+        <windowsSettings xmlns:ws="http://schemas.microsoft.com/SMI/2005/WindowsSettings">
+            <ws:dpiAware>True</ws:dpiAware>
+        </windowsSettings>
+    </application>
+</assembly>
+

files/windows/openmw.rc

@@ -1 +1,2 @@
 IDI_ICON1               ICON    DISCARDABLE     "openmw.ico"
+CREATEPROCESS_MANIFEST_RESOURCE_ID RT_MANIFEST "openmw.exe.manifest"