The rc.exe that comes with the Windows 11 SDK does not allow one to include
winuser.h directly in the .rc scripts, so make sure that we do not try to
generate the final gtk.rc with it, but instead include windows.h with
WIN32_LEAN_AND_MEAN defined.
open() in text mode should never be used without an encoding because it defaults
to the locale encoding which is rarely what is wanted.
This fixes the Windows build in some cases (depending on the locale/paths used)
This will ensure that the version info is easily visible from the
GDK/GTK+ DLLs, and ensure that the print dialogs will have a more modern
look and feel.