Group network-related code together

Originally committed as revision 12371 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/os_support.h

@@ -27,10 +27,6 @@
  * miscellaneous OS support macros and functions.
  */
 
-#ifndef HAVE_SOCKLEN_T
-typedef int socklen_t;
-#endif
-
 #ifdef __MINGW32__
 __declspec(dllimport) void WINAPI Sleep(unsigned long dwMilliseconds);
 // #  include <windows.h>
@@ -56,6 +52,10 @@ __declspec(dllimport) void WINAPI Sleep(unsigned long dwMilliseconds);
 #  endif
 #endif
 
+#ifndef HAVE_SOCKLEN_T
+typedef int socklen_t;
+#endif
+
 /* most of the time closing a socket is just closing an fd */
 #ifndef HAVE_CLOSESOCKET
 #define closesocket close