Set CFSocket option for native size socket handling

Author: splhack

src/MacVim/MMBackend.m

@@ -3448,6 +3448,10 @@ - (id)initWithChannel:(channel_T *)c part:(int)p
                                       kCFSocketReadCallBack,
                                       &socketReadCallback,
                                       &ctx);
+    CFOptionFlags opt = CFSocketGetSocketFlags(socket);
+    opt &= ~(kCFSocketCloseOnInvalidate|
+        kCFSocketAutomaticallyReenableReadCallBack);
+    CFSocketSetSocketFlags(socket, opt);
     runLoopSource = CFSocketCreateRunLoopSource(NULL,
                                                 socket,
                                                 0);