* fhandler.cc (fhandler_base::set_inheritance): Just use DUPLICATE_CLOSE_SOURCE

to change inheritance.  Eliminate all other logic dealing with closed handles.
* fhandler.h (fhandler_base::set_inheritance): Reflect above change.
* fhandler_tty.cc (fhandler_tty_common::set_close_on_exec): Ditto.

winsup/cygwin/fhandler.h

@@ -310,8 +310,7 @@ public:
   unsigned long get_namehash () { return namehash; }
 
   virtual void hclose (HANDLE h) {CloseHandle (h);}
-  virtual void set_inheritance (HANDLE &h, int not_inheriting,
-				const char *name = NULL);
+  virtual void set_inheritance (HANDLE &h, int not_inheriting);
 
   /* fixup fd possibly non-inherited handles after fork */
   void fork_fixup (HANDLE parent, HANDLE &h, const char *name);