It's provided by sys.mk so there's no need to derive it from ${.CURDIR}.
Suggested by: ngie
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5998
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