gtk: Define _WIN32_WINNT and friends as cflags

Instead of scattering them around, define _WIN32_WINNT, WINVER and
NTDDIVER in gtk/meson.build, like what we do in GDK-Win32.

Also, since we are requiring Windows 7 or later in GDK-Win32, do
likewise in GTK, since GDK nowadays is in the same DLL/library as GTK,
so we should make things more uniform.

gtk/gtkfilechoosernativewin32.c

@@ -19,10 +19,6 @@
 
 #include "config.h"
 
-/* Vista or newer */
-#define _WIN32_WINNT 0x0600
-#include <sdkddkver.h>
-
 #define COBJMACROS
 
 #include "gtkfilechoosernativeprivate.h"

gtk/meson.build

@@ -1031,7 +1031,12 @@ if broadway_enabled
 endif
 
 if win32_enabled
-  gtk_cargs += ['-DGTK_PRINT_BACKENDS="file,lpr"']
+  gtk_cargs += [
+    '-DGTK_PRINT_BACKENDS="file,lpr"',
+    '-D_WIN32_WINNT=0x0601',  # Windows 7 or later
+    '-DWINVER=0x0601',
+    '-DNTDDI_VERSION=NTDDI_WIN7',
+  ]
   gtk_deps += [ giowin32_dep, pangowin32_dep ]
 
   gtk_deps += [

gtk/print/gtkprint-win32.c

@@ -16,16 +16,6 @@
  * License along with this library. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef _MSC_VER
-#ifndef _WIN32_WINNT
-/* Vista or newer */
-#define _WIN32_WINNT 0x0600
-#endif
-#ifndef WINVER
-#define WINVER _WIN32_WINNT
-#endif
-#endif
-
 #include "config.h"
 #include "gtkprint-win32.h"
 

gtk/print/gtkprintoperation-win32.c

@@ -16,16 +16,6 @@
  * License along with this library. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef _MSC_VER
-#ifndef _WIN32_WINNT
-/* Vista or newer */
-#define _WIN32_WINNT 0x0600
-#endif
-#ifndef WINVER
-#define WINVER _WIN32_WINNT
-#endif
-#endif
-
 #define COBJMACROS
 #include "config.h"
 #include <math.h>