* arm/arm.c (use_return_insn): Don't use return for naked functions.
	(arm_valid_machine_decl_attribute): New function.
	(arm_naked_function_p): New function.
	(output_func_prologue): Naked functions don't have prologues.
	(arm_expand_prologue): Likewise.
	(output_func_epilogue): Likewise with epilogues.

From-SVN: r11755