Use __WINDOWS__ for OS kind checks and reserve __WXMSW__ for GUI toolkit.

This change prepares the way for using wxGTK under Windows as this would
still define __WINDOWS__ but use __WXGTK__ instead of __WXMSW__.

Closes #14064.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70796 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/private/socket.h

@@ -61,7 +61,7 @@
 
 // include the header defining timeval: under Windows this struct is used only
 // with sockets so we need to include winsock.h which we do via windows.h
-#ifdef __WXMSW__
+#ifdef __WINDOWS__
     #include "wx/msw/wrapwin.h"
 #else
     #include <sys/time.h>   // for timeval
@@ -79,7 +79,7 @@
 
 // define some symbols which winsock.h defines but traditional BSD headers
 // don't
-#ifndef __WXMSW__
+#ifndef __WINDOWS__
     #define SOCKET int
 #endif
 
@@ -367,7 +367,7 @@ private:
     wxDECLARE_NO_COPY_CLASS(wxSocketImpl);
 };
 
-#if defined(__WXMSW__)
+#if defined(__WINDOWS__)
     #include "wx/msw/private/sockmsw.h"
 #else
     #include "wx/unix/private/sockunix.h"