lib: add TCP_CORK wrapper
* sockunion.{c,h}: (sockopt_cork) wrapper for TCP_CORK socket option for
those platforms that provide it. For other platforms, it is just a nop.
diff --git a/lib/sockunion.h b/lib/sockunion.h
index 96b9a0d..91bfbc7 100644
--- a/lib/sockunion.h
+++ b/lib/sockunion.h
@@ -102,6 +102,7 @@
extern int sockunion_bind (int sock, union sockunion *,
unsigned short, union sockunion *);
extern int sockopt_ttl (int family, int sock, int ttl);
+extern int sockopt_cork (int sock, int onoff);
extern int sockunion_socket (union sockunion *su);
extern const char *inet_sutop (union sockunion *su, char *str);
extern enum connect_result sockunion_connect (int fd, union sockunion *su,