launcher: pre-bind System32 dwmapi.dll to avoid shadowing by extra DLL directories

Code/immersive_launcher/Launcher.cpp

@@ -10,6 +10,7 @@
 #include "Utils/FileVersion.inl"
 
 #include "oobe/PathSelection.h"
+#include "SystemDllPreload.h"
 #include "oobe/PathArgument.h"
 #include "oobe/SupportChecks.h"
 #include "steam/SteamLoader.h"
@@ -70,6 +71,7 @@ void SetMaxstdio()
 
 int StartUp(int argc, char** argv)
 {
+    PreloadSystemDlls();
     bool askSelect = (GetAsyncKeyState(VK_SPACE) & 0x8000);
     if (!HandleArguments(argc, argv, askSelect))
         return -1;

Code/immersive_launcher/SystemDllPreload.h

@@ -0,0 +1,28 @@
+#pragma once
+
+// Pre-binds System32 copies of DLLs that could otherwise be shadowed by the
+// extra DLL directories STR registers (the Steam folder, see
+// steam/SteamLoader.cpp). Windows reuses an already-loaded module for
+// same-name imports, so a later import of dwmapi.dll gets this one.
+// Call at the very start of launcher::StartUp().
+//
+// Deliberately NOT listed: d3d11/dxgi/d3d9/dinput8/version, which ENB,
+// ReShade etc. intentionally proxy from the game folder.
+
+#include <Windows.h>
+
+namespace launcher
+{
+inline void PreloadSystemDlls()
+{
+    static const wchar_t* const kSystemOnly[] = {
+        L"dwmapi.dll",
+    };
+
+    for (const wchar_t* name : kSystemOnly)
+    {
+        // Searches System32 only. Never freed, so it stays resident.
+        LoadLibraryExW(name, nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32);
+    }
+}
+} // namespace launcher