* arm-tdep.c (arm_mode_strings, arm_fallback_mode_string)

	* arm-tdep.c (arm_mode_strings, arm_fallback_mode_string)
	(arm_force_mode_string, arm_show_fallback_mode)
	(arm_show_force_mode): New.
	(arm_pc_is_thumb): Honor fallback-mode and force-mode.  Use
	arm_frame_is_thumb.
	(_initialize_arm_tdep): Add "set arm fallback-mode"
	and "set arm force-mode".
	* NEWS: Document new commands.

	* gdb.texinfo (ARM): Document set/show arm fallback-mode
	and set/show arm force-mode.