Prevent writes to R15 via LDR or LDM from changing the ARM/Thumb state in pre-v5 architectures.

	PR sim/8388
	* armemu.c (WriteR15Load): New function.  Determines if the state
	can be changed upon a write to R15.
	(LoadMult): Use WriteR15Load.
	* armemu.h (WRITEDESTB): Use WriteR15Load.
Add support for instruction level tracing to the ARM simulator.

	* wrapper.c (op_print): New function.
	(sim_dis_read): New function.
	(print_insn): New function - disassembles the given instruction.
	(sim_trace): Note that tracing is now allowed.
	(sim_create_inferior): Default to emulating v6.
	Initialise the disassembler machinery.
	(sim_target_parse_command_line): Add support for -t -d and -z
	options.
	(sim_target_display_usage): Note existence of -d and -z options.
	(sim_open): Parse -t -d and -z options.
	* armemu.h: Add exports of trace, disas and trace_funcs.
	Add prototype for print_insn.
	* armemu.c (ARMul_Emulate26): Add tracing code.
	Delete unused variables.
	* thumbemu (handle_v6_thumb_insn): Delete unused variable Rd.
	Move Rm variable into switch cases.
	Add tracing code.

	* armcopro.c (XScale_cp15_init): Add a return value.
	(XScale_cp13_init): Likewise.
	(XScale_cp14_init): Likewise.
	(XScale_cp15_LDC): Delete unused function.
	(XScale_cp15_STC): Likewise.
	* maverick.c: Delete comment inside comment.
	(DSPInit): Delete unused function.
	(DSPMCR4): Fix compile time warning about missing parenthesis.
	(DSPMCR5): Likewise.
	(DSPCDP6): Delete unused variable opcode2.