Fix udp:setpeername("*")

There seems to be a curious difference between MacOS and
Linux and I am not sure if this is documented. When you
break a "connection" on Mac OS, you only eliminate the peer
association, but the local address remains bound. On Linux,
breaking a "connection" eliminates the binding to the local
address. Have you guys ever come accross this?

Another irritating difference is that connect() returns the
error EAFNOSUPPORT on Mac OS. I am going to ignore all
errors when the reason for calling connect() is simply to
break the "connection".

.gitignore

@@ -1,3 +1,4 @@
 *.o
 *.so
 *.so.*
+mac