Remove all #if 0'd code.

	Remove all #if 0'd code.
	* filter.c: Remove #if 0'd function it_is.
	(main): Remove #if 0'd code.
	* gen-engine.c: Remove #if 0'd functions print_jump,
	print_jump_insn, print_jump_definition,
	print_jump_internal_function, print_jump_body.
	(gen_engine_c): Remove #if 0'd code.
	* gen-idecode.c: Remove #if 0'd functions print_jump print_jump,
	print_jump_insn, print_jump_definition,
	print_jump_internal_function, print_jump_until_stop_body.
	* gen-model.c: Remove #if 0'd functions model_c_or_h_data,
	model_c_or_h_function, gen_model_h, model_c_insn,
	model_c_function, gen_model_c and types model_c_passed_data
	and struct _model_c_passed_data.
	* gen.c: Remove #if 0'd type constant_field_types and function
	insn_field_is_constant.
	(gen_entry_find_opcode_field): Remove #if 0'd code.
	* ld-insn.c (parse_insn_model_record): Remove #if 0'd code.
	* misc.h (STRDUP, STRNDUP): Remove #if 0'd macros.