prevent hangs in server.Server._do_accept by making listening sockets nonblocking.

--HG--
extra : transplant_source : %0Ed%0B%01T%13%5DU0%C5%EF/%EC%A9%0D%A1%F1%E9%BDp

gevent/baseserver.py

@@ -193,5 +193,6 @@ def _tcp_listener(address, backlog=50, reuse_addr=None):
         sock.setsockopt(_socket.SOL_SOCKET, _socket.SO_REUSEADDR, reuse_addr)
     sock.bind(address)
     sock.listen(backlog)
+    sock.setblocking(0)
     return sock
 

gevent/server.py

@@ -111,7 +111,14 @@ class StreamServer(BaseServer):
             if self.full():
                 self.stop_accepting()
                 return
-            client_socket, address = self.socket.accept()
+            try:
+                client_socket, address = self.socket.accept()
+            except socket.error, err:
+                if err[0]==errno.EAGAIN:
+                    sys.exc_clear()
+                    return
+                raise
+
             self.delay = self.min_delay
             client_socket = socket.socket(_sock=client_socket)
             spawn = self.spawn