egl: Detect Windows platform using GDI

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Reviewed By: Bill Kristiansen <billkris@microsoft.com>

Acked-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12727>

src/egl/main/egldisplay.c

@@ -64,6 +64,9 @@
 #ifdef HAVE_DRM_PLATFORM
 #include <gbm.h>
 #endif
+#ifdef HAVE_WINDOWS_PLATFORM
+#include <windows.h>
+#endif
 
 
 /**
@@ -128,6 +131,11 @@ _eglNativePlatformDetectNativeDisplay(void *nativeDisplay)
    if (nativeDisplay == EGL_DEFAULT_DISPLAY)
       return _EGL_INVALID_PLATFORM;
 
+#ifdef HAVE_WINDOWS_PLATFORM
+   if (GetObjectType(nativeDisplay) == OBJ_DC)
+      return _EGL_PLATFORM_WINDOWS;
+#endif
+
 #if defined(HAVE_WAYLAND_PLATFORM) || defined(HAVE_DRM_PLATFORM)
    if (_eglPointerIsDereferencable(nativeDisplay)) {
       void *first_pointer = *(void **) nativeDisplay;