Would like to use ARCH (uname -p) but it's not always correct (e.g. arm64)

Hello all,

I'm looking for the best way to use `uname -m` on plist_sub:
---
UNAME_M_CMD=    ${UNAME} -m
PLIST_SUB+=     ARCH="$$(${UNAME_M_CMD})"
---
but I'm not sure sure about -m and -p differences and effects on
arm64/aarch64.

It would be nicer to use:
---
PLIST_SUB+= ARCH=${ARCH}
---
but it uses `uname -p`

Is this still an issue?
I saw this example on security/zeek and I need this for x11-wm/nscde.

Thanks,

-- 
Nuno Teixeira
FreeBSD Committer (ports)