target: allow decr_pc_after_break to be defined by the target

target: allow decr_pc_after_break to be defined by the target

Allow the target to define which value to use in decr_pc_after_break.
It defaults to gdbarch_decr_pc_after_break (GDBARCH).

2014-01-16  Markus Metzger  <markus.t.metzger@intel.com>

	* target.h (struct target_ops) <to_decr_pc_after_break>: New.
	(forward_target_decr_pc_after_break)
	(target_decr_pc_after_break): New.
	* target.c (forward_target_decr_pc_after_break)
	(target_decr_pc_after_break): New.
	* aix-thread.c (aix_thread_wait): Call target_decr_pc_after_break
	instead of gdbarch_decr_pc_after_break.
	* darwin-nat.c (cancel_breakpoint): Call target_decr_pc_after_break
	instead of gdbarch_decr_pc_after_break.
	* infrun.c (adjust_pc_after_break): Call target_decr_pc_after_break
	instead of gdbarch_decr_pc_after_break.
	* linux-nat.c (cancel_breakpoint): Call target_decr_pc_after_break
	instead of gdbarch_decr_pc_after_break.
	* linux-thread-db.c (check_event): Call target_decr_pc_after_break
	instead of gdbarch_decr_pc_after_break.
	* record-full.c (record_full_wait_1): Call target_decr_pc_after_break
	instead of gdbarch_decr_pc_after_break.