* target.h (class Target): Add osabi_ field.

	* target.h (class Target): Add osabi_ field.
	(Target::osabi): New function.
	(Target::set_osabi): New function.
	(Target::Target): Initialize osabi_.
	(Target::do_adjust_elf_header): Make pure virtual.
	(Sized_target::do_adjust_elf_header): Declare.
	* target.cc (Sized_target::do_adjust_elf_header): New function.
	(class Sized_target): Instantiate all versions.
	* freebsd.h (class Target_freebsd): Remove.
	(Target_selector_freebsd::do_recognize): Call set_osabi on
	Target.
	(Target_selector_freebsd::do_recognize_by_name): Likewise.
	(Target_selector_freebsd::set_osabi): Remove.
	* i386.cc (class Target_i386): Inherit from Sized_target rather
	than Target_freebsd.
	* x86_64.cc (class Target_x86_64): Likewise.