Updated gdbserver, using new PTRACE_GETREGSETS and PTRACE_SETREGSETS
functionality, and without dependency on the GDB source.

In gdb:

2013-02-27  Jeremy Bennett <jeremy.bennett@embecosm.com>

	* regformats/reg-arc.dat: Updated to match new GDB register
	sequence.

In gdb/gdbserver:

2013-02-27  Jeremy Bennett <jeremy.bennett@embecosm.com>

	* configure.srv (arc*-*-linux*): Remove srv_linux_usrregs and
	replace with srv_linux_regsets.
	* linux-arc-low.c: Commenting updated throughout.
	(regdef.h): Include file added.
	(../arc-constants.h, asm/trace.h): Include files removed
	(elf.h, linux/ptrace.h): Added.
	(ARC_NR_REGS): Removed throughout, replaced where appropriate by
	arc_num_regs.
	(arc_regmap): Removed.
	(struct user_regs_struct) [ARC_LEGACY_PTRACE_ABI]: Added
	conditionally to define struture, pending its adoption in mainline
	Linux.
	(orig_r8): Created to track latest value of orig_r8 register.
	(arc_num_regs): Created.
	(init_registers_arc): Declared as extern.
	(arc_arch_setup): Initialize arc_num_regs from regcache size.
	(arc_get_pc): Name of register is changed.
	(arc_set_pc): Rewritten to use new register structure.
	(arc_fill_gregset, arc_store_gregset): Created.
	(target_regsets): Created.
	(the_low_target): Reordered to omit obsolete functions and
	variables and use named elements.