convert to_get_thread_local_address to use target delegation

convert to_get_thread_local_address to use target delegation

This converts to_get_thread_local_address to use
TARGET_DEFAULT_NORETURN.  One possible oddity is that this changes the
text of the kind of exception thrown in some cases.  This doesn't seem
to be a problem; in fact perhaps the final call to 'error' in
target_translate_tls_address should be changed to call
generic_tls_error.

2014-07-07  Tom Tromey  <tromey@redhat.com>

	* target.h (struct target_ops) <to_get_thread_local_address>: Use
	TARGET_DEFAULT_NORETURN.
	* target.c (generic_tls_error): New function.
	(target_translate_tls_address): Don't search target stack.
	* target-delegates.c: Rebuild.
	* ppc-linux-tdep.c (ppc_linux_spe_context): Don't search target
	stack.
	* linux-thread-db.c (thread_db_get_thread_local_address):
	Unconditionally call beneath target.