batch of fixes and enhancements - early january'2025

[rpardini]

further enhancements:

• can now build (and develop) Hook for any arch under any arch, including for amd64 under Darwin arm64
• full support for building on macOS+brew, including on arm64
• added shellfmt tool and bash code format enforcing on CI (in addition to shellcheck)
• avoid pulling skopeo image over and over again

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build: implement shellfmt (and lint which does both shellcheck/fmt)

• for consistent bash formatting
• include an .editorconfig for IDE's

gha: switch to lint (which does both shellcheck and shellfmt)

linuxkit: bump 1.5.2 -> 1.5.3

build: implement build-host dependency handling for macOS+brew

• if on macOS+brew:
  • detects missing deps and installs them with brew
  • exports PATH with brew-based GNU versions first
    • coreutils, gnu-sed and gnu-tar included

build: Dockerfile: fix FROM xx AS casing

• to squash recent BuildKit warnings

build: pass --verbose 2 to linuxkit if DEBUG=yes

• can help with some edge cases

build: refactor skopeo pull and list-tags functions

• this only affects Armbian kernel flavours
• avoids pulling if found in local cache

build: use skopeo v1.17.0 instead of latest

• since we now use the local tag

build: armbian: kernel: refactor Dockerfile with helper

• building the Armbian kernels would produce different hashes depending on the arch of the host
• moving the affected code into the Dockerfile would lead to escaping pain; instead implement a docker.sh helper
• in practice, all code in the Dockerfile is hashed, but the arch decision is now therein and hash won't change
• also, allows for reuse, which is bound to come later

build: docker: detect & export DOCKER_HOST from current docker context

• Some Docker-in-VM solutions (like Docker Desktop, colima, etc) set a non-default docker context pointing to the correct socket
• Seems LinuxKit fumbles detecting this and ends up silently failing all local-Docker-daemon cache hits
  • that is fine for CI, where all images are (beforehand) pushed to the registry (and thus LK ends up pulling from remote), but not during local development
  • reported to upstream LinuxKit: doesn't respect docker context (colima, Docker Desktop) and fails --docker lookups silently linuxkit/linuxkit#4092

build: kernel: force target arch on cross-built kernel docker image manifest

• our kernel builds are done in arch-independent Dockerfiles
• but those get the build-host's architecture, despite the contents being correct
• when locally developing on a kernel that is != host-arch
  • those get the host-arch in the image
  • but LinuxKit refuses to use it due to arch mismatch
• (when pushed to a registry, the arch info is discarded, and LK is ok with that)
• thus
  • introduce ensure_docker_image_architecture(imagetag, arch)
    • which just hacks at manifests via a docker save/docker load
  • call it from both default and armbian kernel builds

build: docker: avoid Docker Inc's "What's next" hints

• enough spam already, thanks

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Signed-off-by: Ricardo Pardini ricardo@pardini.net