* arm.cc (Target_arm::do_is_defined_by_abi): Make sym a const

	* arm.cc (Target_arm::do_is_defined_by_abi): Make sym a const
	pointer.
	(Stub_addend_reader::operator()): Declare Arm_relocate_functions
	as a class, not a struct.
	(Target_arm::scan_span_for_cortex_a8_erratum): Likewise.
	(Target_arm::apply_cortex_a8_workaround): Likewise.
	* gc.h: Declare Reloc_types as a struct, not a class.
	* object.h: Declare Symbols_data as a struct.
	* reloc.h: Declare Read_relocs_data as a struct.
	* target.h: Declare Relocate_info as a struct.