have build container only claim port 1313 if running make serve

[craigbox]

You can only run the build container once, because it port-forwards port 1313.

Makefile.overrides.mk:CONTAINER_OPTIONS = -p 1313:1313 ${ADDITIONAL_CONTAINER_OPTIONS}

This is only necessary if you're using it to run a local Hugo preview, and it stops you being able to do useful things like make gen or make lint-md while it's running.

Is it practical to run this container more than once at once, and if so, can we have this variable only set when the target for make serve is run?

Affected product area (please put an X in all that apply)

[x] Docs
[x] Test and Release

[zirain]

is this for istio.io repo?

[craigbox]

Yes, sorry, I thought it was one of the common files. I'll move the issue to the right repo!