[Differential] [Request, 6 lines] D2302: Add arm64 to universe if binutils is available

[emaste (Ed Maste)]

emaste created this revision.
emaste added reviewers: imp, andrew.
emaste added a subscriber: freebsd-toolchain.

REVISION SUMMARY
  arm64 relies on an external binutils port or package because the in-tree linker from binutils 2.17.50 does not support arm64. Add arm64 to universe if the linker is available.
  
  buildworld and buildkernel use the external binutils automatically, so `pkg install aarch64-binutils` is sufficient for building FreeBSD/arm64.

REVISION DETAIL
  https://reviews.freebsd.org/D2302

AFFECTED FILES
  Makefile

To: emaste, imp, andrew
Cc: freebsd-toolchain