go32-nat.c: Don't install a deprecated_xfer_memory method.

This removes yet another instance of a deprecated_xfer_memory user.

Unfortunately djgpp's write_child function takes a non-const buffer
pointer, while GDB's xfer_partial api passes a const pointer.  To be
const-correct, we need to copy that buffer to a non-const buffer, and
pass the copy to write_child.  This is actually what
target.c:default_xfer_partial itself does, when calling into the
ops->deprecated_xfer_memory hook.

Tested by cross-building djgpp gdb, on x86-64 Fedora 17.

gdb/
2014-01-16  Pedro Alves  <palves@redhat.com>

	* go32-nat.c (my_write_child): New function.
	(go32_xfer_memory): Rewrite as to_xfer_partial helper.
	(go32_xfer_partial): New function.
	(init_go32_ops): Don't install a deprecated_xfer_memory hook.
	Instad a to_xfer_partial hook.
eliminate target_ops->deprecated_xfer_memory.

As no target uses it anymore, it can finaly go away.

After removing the deprecated_xfer_memory handling from
default_xfer_partial, we can delete the latter, because the only thing
it does is delegate to the target beneath unconditionally, which is
what the delegator installed by target-delegates.c will do for us if
no to_xfer_partial method is installed.

This was the last user of de_fault, so that goes away too.

Tested on x86_64 Fedora 17.

gdb/
2014-01-16  Pedro Alves  <palves@redhat.com>

	* target.c (complete_target_initialization): Don't install
	default_xfer_partial as to_xfer_partial hook.
	(nomemory): Delete.
	(update_current_target): Don't INHERIT nor de_fault
	deprecated_xfer_memory.  Delete de_fault macro.
	(default_xfer_partial, deprecated_debug_xfer_memory): Delete.
	(setup_target_debug): Don't install a deprecated_xfer_memory hook.
	* target.h (struct target_ops) <deprecated_xfer_memory>: Delete
	field.
bsd-uthread.c: Don't install a to_xfer_partial method.

Not sure whether the comment about deprecated_xfer_memory was ever
true (it hasn't been in recent years), but in any case,
deprecated_xfer_memory is gone now.  No need to install an target
method that just delegates, as that's what the default delagator does
already.

gdb/
2014-01-15  Pedro Alves  <palves@redhat.com>

	* bsd-uthread.c (bsd_uthread_xfer_partial): Delete function.
	(bsd_uthread_target): Don't install bsd_uthread_xfer_partial as
	to_xfer_partial method.