GDB: Add support for the new set/show disassembler-options commands.

GDB: Add support for the new set/show disassembler-options commands.

This commit adds support to GDB so that it can modify the disassembler-options
value that is passed to the disassembler, similar to objdump's -M option.
Currently, the only supported targets are ARM, PowerPC and S/390, but
adding support for a new target(s) is not difficult.

include/
	* dis-asm.h (disasm_options_t): New typedef.
	(parse_arm_disassembler_option): Remove prototype.
	(set_arm_regname_option): Likewise.
	(get_arm_regnames): Likewise.
	(get_arm_regname_num_options): Likewise.
	(disassemble_init_s390): New prototype.
	(disassembler_options_powerpc): Likewise.
	(disassembler_options_arm): Likewise.
	(disassembler_options_s390): Likewise.
	(remove_whitespace_and_extra_commas): Likewise.
	(disassembler_options_cmp): Likewise.
	(next_disassembler_option): New inline function.
	(FOR_EACH_DISASSEMBLER_OPTION): New macro.

opcodes/
	* disassemble.c Include "safe-ctype.h".
	(disassemble_init_for_target): Handle s390 init.
	(remove_whitespace_and_extra_commas): New function.
	(disassembler_options_cmp): Likewise.
	* arm-dis.c: Include "libiberty.h".
	(NUM_ELEM): Delete.
	(regnames): Use long disassembler style names.
	Add force-thumb and no-force-thumb options.
	(NUM_ARM_REGNAMES): Rename from this...
	(NUM_ARM_OPTIONS): ...to this.  Use ARRAY_SIZE.
	(get_arm_regname_num_options): Delete.
	(set_arm_regname_option): Likewise.
	(get_arm_regnames): Likewise.
	(parse_disassembler_options): Likewise.
	(parse_arm_disassembler_option): Rename from this...
	(parse_arm_disassembler_options): ...to this.  Make static.
	Use new FOR_EACH_DISASSEMBLER_OPTION macro to scan over options.
	(print_insn): Use parse_arm_disassembler_options.
	(disassembler_options_arm): New function.
	(print_arm_disassembler_options): Handle updated regnames.
	* ppc-dis.c: Include "libiberty.h".
	(ppc_opts): Add "32" and "64" entries.
	(ppc_parse_cpu): Use ARRAY_SIZE and disassembler_options_cmp.
	(powerpc_init_dialect): Add break to switch statement.
	Use new FOR_EACH_DISASSEMBLER_OPTION macro.
	(disassembler_options_powerpc): New function.
	(print_ppc_disassembler_options): Use ARRAY_SIZE.
	Remove printing of "32" and "64".
	* s390-dis.c: Include "libiberty.h".
	(init_flag): Remove unneeded variable.
	(struct s390_options_t): New structure type.
	(options): New structure.
	(init_disasm): Rename from this...
	(disassemble_init_s390): ...to this.  Add initializations for
	current_arch_mask and option_use_insn_len_bits_p.  Remove init_flag.
	(print_insn_s390): Delete call to init_disasm.
	(disassembler_options_s390): New function.
	(print_s390_disassembler_options): Print using information from
	struct 'options'.
	* po/opcodes.pot: Regenerate.

binutils/
	* objdump.c (main): Use remove_whitespace_and_extra_commas.

gdb/
	* NEWS: Mention new set/show disassembler-options commands.
	* doc/gdb.texinfo: Document new set/show disassembler-options commands.
	* disasm.c: Include "arch-utils.h", "gdbcmd.h" and "safe-ctype.h".
	(prospective_options): New static variable.
	(gdb_disassembler::gdb_disassembler): Initialize
	m_di.disassembler_options.
	(gdb_buffered_insn_length_init_dis): Initilize di->disassembler_options.
	(get_disassembler_options): New function.
	(set_disassembler_options): Likewise.
	(set_disassembler_options_sfunc): Likewise.
	(show_disassembler_options_sfunc): Likewise.
	(disassembler_options_completer): Likewise.
	(_initialize_disasm): Likewise.
	* disasm.h (get_disassembler_options): New prototype.
	(set_disassembler_options): Likewise.
	* gdbarch.sh (gdbarch_disassembler_options): New variable.
	(gdbarch_verify_disassembler_options): Likewise.
	* gdbarch.c: Regenerate.
	* gdbarch.h: Likewise.
	* arm-tdep.c (num_disassembly_options): Delete.
	(set_disassembly_style): Likewise.
	(arm_disassembler_options): New static variable.
	(set_disassembly_style_sfunc): Convert short style name into long
	option name.  Call set_disassembler_options.
	(show_disassembly_style_sfunc): New function.
	(arm_gdbarch_init): Call set_gdbarch_disassembler_options and
	set_gdbarch_verify_disassembler_options.
	(_initialize_arm_tdep): Delete regnames variable and update callers.
	(arm_disassembler_options): Initialize.
	(disasm_options): New variable.
	(num_disassembly_options): Rename from this...
	(num_disassembly_styles): ...to this.  Compute by scanning through
	disasm_options.
	(valid_disassembly_styles): Initialize using disasm_options.
	Remove calls to parse_arm_disassembler_option, get_arm_regnames and
	set_arm_regname_option.
	Pass show_disassembly_style_sfunc to the "disassembler" setshow command.
	* rs6000-tdep.c (powerpc_disassembler_options): New static variable.
	(rs6000_gdbarch_init): Call set_gdbarch_disassembler_options and
	set_gdbarch_verify_disassembler_options.
	* s390-tdep.c (s390_disassembler_options): New static variable.
	(s390_gdbarch_init):all set_gdbarch_disassembler_options and
	set_gdbarch_verify_disassembler_options.

gdb/testsuite/
	* gdb.arch/powerpc-power.exp: Delete test.
	* gdb.arch/powerpc-power.s: Likewise.
	* gdb.disasm/disassembler-options.exp: New test.
	* gdb.arch/powerpc-altivec.exp: Likewise.
	* gdb.arch/powerpc-altivec.s: Likewise.
	* gdb.arch/powerpc-altivec2.exp: Likewise.
	* gdb.arch/powerpc-altivec2.s: Likewise.
	* gdb.arch/powerpc-altivec3.exp: Likewise.
	* gdb.arch/powerpc-altivec3.s: Likewise.
	* gdb.arch/powerpc-power7.exp: Likewise.
	* gdb.arch/powerpc-power7.s: Likewise.
	* gdb.arch/powerpc-power8.exp: Likewise.
	* gdb.arch/powerpc-power8.s: Likewise.
	* gdb.arch/powerpc-power9.exp: Likewise.
	* gdb.arch/powerpc-power9.s: Likewise.
	* gdb.arch/powerpc-vsx.exp: Likewise.
	* gdb.arch/powerpc-vsx.s: Likewise.
	* gdb.arch/powerpc-vsx2.exp: Likewise.
	* gdb.arch/powerpc-vsx2.s: Likewise.
	* gdb.arch/powerpc-vsx3.exp: Likewise.
	* gdb.arch/powerpc-vsx3.s: Likewise.
	* gdb.arch/arm-disassembler-options.exp: Likewise.
	* gdb.arch/powerpc-disassembler-options.exp: Likewise.
	* gdb.arch/s390-disassembler-options.exp: Likewise.