Make the self-hosted kernel-build runnable with zero manual toolchain/python setup
on the runner host (docs/ci-cd.md steps 3-4 move into the workflow):
- build/build-kernel.sh: honor a caller-provided CROSS_COMPILE (default stays the
Luckfox uclibc prefix). The kernel is freestanding, so a generic arm cross
compiler links it.
- kernel-build job: set CROSS_COMPILE=arm-linux-gnueabihf- (Debian
gcc-arm-linux-gnueabihf, already on 0640) instead of depending on the ephemeral
SDK checkout path; symlink python->python3 into $RUNNER_TEMP/bin on $GITHUB_PATH
for the bare-`python` SDK quirk.
- docs/ci-cd.md: only steps 1-2 (systemd service + cgroup cap) still need 0640 sudo.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017wB8KB3MMQztRDXCMCkPrf
