Extract setting WINVER/_WIN32_WINNT to a separate file

This will allow reusing it from other places.

include/wx/msw/wrapwin.h

@@ -12,6 +12,10 @@
 
 #include "wx/platform.h"
 
+// before including windows.h, define version macros at (currently) maximal
+// values because we do all our checks at run-time anyhow
+#include "wx/msw/winver.h"
+
 // strict type checking to detect conversion from HFOO to HBAR at compile-time
 #ifndef STRICT
     #define STRICT 1
@@ -24,25 +28,6 @@
 #endif // NOMINMAX
 
 
-// before including windows.h, define version macros at (currently) maximal
-// values because we do all our checks at run-time anyhow
-#ifndef WINVER
-    #define WINVER 0x0603
-#endif
-
-// define _WIN32_WINNT and _WIN32_IE to the highest possible values because we
-// always check for the version of installed DLLs at runtime anyway (see
-// wxGetWinVersion() and wxApp::GetComCtl32Version()) unless the user really
-// doesn't want to use APIs only available on later OS versions and had defined
-// them to (presumably lower) values
-#ifndef _WIN32_WINNT
-    #define _WIN32_WINNT 0x0603
-#endif
-
-#ifndef _WIN32_IE
-    #define _WIN32_IE 0x0700
-#endif
-
 // For IPv6 support, we must include winsock2.h before winsock.h, and
 // windows.h include winsock.h so do it before including it
 #if wxUSE_IPV6