circleci: fix build for ARM

[nandahkrishna]

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This should hopefully get circleci built on ARM. I tried (for a few hours 😅) to remove GOPATH and get this built with our usual std_go_args, but it fails. Some observations:

• packr doesn't seem to be compatible with the -trimpath flag, although I'm not too familiar with any of this.
• Even without using -trimpath, removing GOPATH results in a binary that fails to work, with an error message indicating that data.yml couldn't be found (this is the resource that packr is used to handle).

I'm attaching a patch with one of my approaches, hopefully it helps someone more experienced debug the issue: circleci.patch.txt.

[carlocab]

This seems fine to me, but adding automerge-skip in case someone else gets the chance to have a look.

[nandahkrishna]

Seems like packr wasn't walking the directories like it was supposed to when removing GOPATH. Even when building in the checked out repository, moving the resulting binary elsewhere caused problems. I seem to have got it to work using the --ignore-imports flag for packr2, which forces the behaviour we need. Using -trimpath also works now, my earlier statement was based on an issue with an older version of packr.

I'm going to try asking upstream if they can move away from using packr, as it doesn't seem to be actively maintained. The last commit was in Nov 2020 along with the latest release, and there's some discussion in gobuffalo/packr#252. Also, there's a note in the README pointing to an alternative to use instead.

[BrewTestBot]

🤖 A scheduled task has triggered a merge.