Ports: how to install dependencies from binaries?

Hi all,

Silly question… how do you install the dependencies of a port from
binaries automatically?

Situation is this: I'm wanting to add OPUS support to Asterisk as I have
an ATA that supports this CODEC, it'd nice to be able to transcode this
to other formats. I have a work-in-progress patch to the 'asterisk'
port for doing this (modelled on what's being done for 'asterisk-speex')
that I'll share once I've done some testing on both versions.

I have two VMs running, one with OpenBSD 6.6 (which I am running on my
router) and one with OpenBSD current (snapshot made on Monday).

`make install-all` in the `asterisk` port seems to want to drag in the
kitchen sink. The only thing I really want to compile is Asterisk
itself (with my patch).

Is there a command that installs the ports' build dependencies via
`pkg_add` or do I need to extract the dependencies by other means and
manually install them?

Regards,
--
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
...it's backed up on a tape somewhere.