ELF Tool Chain elfcopy is nearly a drop-in replacement for GNU objcopy,
but does not currently support PE output which is needed for building
x86 UEFI bits.
Add a src.conf knob to allow installing it as objcopy and set it by
default for aarch64 only, where we don't have a native binutils.
Reviewed by: bapt
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2887
Set WITH_ELFTOOLCHAIN_TOOLS in src.conf to use the elftoolchain version
of the following tools:
* addr2line
* elfcopy (strip / mcs)
* nm
* size
* strings
Reviewed by: bapt (earlier version)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D1224
