ci: add debug to trace install path #58

	name: CI

	on:
	push:
	branches: [main]
	pull_request:

	jobs:
	build:
	name: build (linux x86_64, mcpp)
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4

	- name: Install xlings
	env:
	XLINGS_VERSION: 0.4.30
	run: \|
	tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
	curl -fsSL -o "/tmp/${tarball}" \
	"https://github.com/d2learn/xlings/releases/download/v${XLINGS_VERSION}/${tarball}"
	tar -xzf "/tmp/${tarball}" -C /tmp
	"/tmp/xlings-${XLINGS_VERSION}-linux-x86_64/subos/default/bin/xlings" self install
	echo "$HOME/.xlings/subos/current/bin" >> "$GITHUB_PATH"

	- name: Install workspace tools (.xlings.json → mcpp 0.0.11)
	run: xlings install -y

	# Cache mcpp's self-bootstrapped sandbox (musl-gcc + binutils +
	# glibc + ninja + patchelf, ~800 MB). Toolchain set is pinned by
	# mcpp 0.0.11, so a fixed key suffices.
	- name: Cache mcpp sandbox
	uses: actions/cache@v4
	with:
	path: ~/.xlings/data/xpkgs/xim-x-mcpp/0.0.11/registry
	key: mcpp-sandbox-${{ runner.os }}-mcpp0.0.11-v2

	- name: Update package index
	run: mcpp index update

	- name: Debug mcpp env
	run: \|
	mcpp self env
	echo "--- xpkgs directory ---"
	find $(mcpp self env 2>&1 \| grep MCPP_HOME \| awk -F'= ' '{print $2}')/registry/data/xpkgs -maxdepth 2 -type d 2>/dev/null \|\| echo "no xpkgs dir"
	echo "--- xlings global data ---"
	ls ~/.xlings/data/xpkgs/ 2>/dev/null \| head -20 \|\| echo "no global xpkgs"

	- name: Build with mcpp
	run: mcpp build

Provide feedback