Include os_support.h only when needed

Originally committed as revision 11073 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avformat.h

@@ -890,8 +890,6 @@ int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size);
 
 #ifdef HAVE_AV_CONFIG_H
 
-#include "os_support.h"
-
 void __dynarray_add(unsigned long **tab_ptr, int *nb_ptr, unsigned long elem);
 
 #ifdef __GNUC__

libavformat/os_support.c

@@ -23,6 +23,7 @@
 #include "avformat.h"
 #include <unistd.h>
 #include <fcntl.h>
+#include "os_support.h"
 
 #ifndef HAVE_SYS_POLL_H
 #ifdef HAVE_WINSOCK2_H

libavformat/tcp.c

@@ -21,6 +21,7 @@
 #include "avformat.h"
 #include <unistd.h>
 #include "network.h"
+#include "os_support.h"
 #include <sys/time.h>
 
 typedef struct TCPContext {

libavformat/udp.c

@@ -21,6 +21,7 @@
 #include "avformat.h"
 #include <unistd.h>
 #include "network.h"
+#include "os_support.h"
 
 #ifndef IPV6_ADD_MEMBERSHIP
 #define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP