udp: Fix compiling with mingw.

https://bugzilla.gnome.org/show_bug.cgi?id=672880

configure.ac

@@ -154,6 +154,9 @@ AX_CREATE_STDINT_H
 dnl used in gst/udp
 AC_CHECK_HEADERS([sys/time.h])
 
+dnl used in gst/udp
+AC_CHECK_HEADERS([sys/socket.h])
+
 dnl *** checks for types/defines ***
 
 dnl Check for FIONREAD ioctl declaration.  This check is needed

gst/udp/gstmultiudpsink.c

@@ -40,7 +40,9 @@
 #include "gstmultiudpsink.h"
 
 #include <string.h>
+#ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
+#endif
 
 #include "gst/glib-compat-private.h"
 

gst/udp/gstudpsrc.c

@@ -112,7 +112,9 @@
 
 #include <gst/net/gstnetaddressmeta.h>
 
+#ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
+#endif
 
 GST_DEBUG_CATEGORY_STATIC (udpsrc_debug);
 #define GST_CAT_DEFAULT (udpsrc_debug)