Support sizehint in _fileobject.readlines, as documented.
diff --git a/Lib/socket.py b/Lib/socket.py
index b28de1d..7658c07 100644
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -228,10 +228,14 @@
         data, self._rbuf = self._rbuf[:i], self._rbuf[i:]
         return data
 
-    def readlines(self):
+    def readlines(self, sizehint = 0):
+        total = 0
         list = []
         while 1:
             line = self.readline()
             if not line: break
             list.append(line)
+            total += len(line)
+            if sizehint and total >= sizehint:
+                break
         return list