url_write is part of the public API so it may not be under ifdef.

Also fixes a compile error if all muxers and protocols are disabled.
Patch by Guillaume LECERF (foxcore gmail com)

Originally committed as revision 11469 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avio.c

@@ -110,7 +110,6 @@ int url_read(URLContext *h, unsigned char *buf, int size)
     return ret;
 }
 
-#if defined(CONFIG_MUXERS) || defined(CONFIG_PROTOCOLS)
 int url_write(URLContext *h, unsigned char *buf, int size)
 {
     int ret;
@@ -122,7 +121,6 @@ int url_write(URLContext *h, unsigned char *buf, int size)
     ret = h->prot->url_write(h, buf, size);
     return ret;
 }
-#endif //CONFIG_MUXERS || CONFIG_PROTOCOLS
 
 offset_t url_seek(URLContext *h, offset_t pos, int whence)
 {