* select.cc: Set errno using set_sig_errno() throughout.

* signal.cc (signal): Always set SA_RESTART flag.
	* syscalls.cc (_read): Revert previous patch.

winsup/cygwin/syscalls.cc

@@ -314,7 +314,6 @@ _read (int fd, void *ptr, size_t len)
 	debug_printf ("non-interruptible read\n");
       else if (!cfd->ready_for_read (fd, wait))
 	{
-	  set_sig_errno (get_errno ());
 	  res = -1;
 	  goto out;
 	}