In FreeBSD 11 ELF Tool Chain's elfcopy is installed as objcopy by default, with the option to switch back to GNU objcopy by setting WITHOUT_ELFCOPY_AS_OBJCOPY in make.conf.
We plan to remove the outdated in-tree binutils in FreeBSD 12, so this option can be removed.
Note: I will hold off on committing these tool chain changes until after FreeBSD 11.0 is released.