nix: define CGO_CPPFLAGS to prioritize nix LLVM headers #32

	name: Nix

	on:
	pull_request:
	push:

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true

	jobs:
	nix-test:
	runs-on: ubuntu-latest
	steps:
	- name: Uninstall system LLVM packages exept LLVM 18
	run: \|
	sudo apt remove llvm-16 llvm-17 -y
	- name: Trap Target.def header
	run: \|
	sudo echo '#error("nope")' \| sudo tee /usr/include/llvm-18/llvm/Config/Targets.def
	- name: Checkout
	uses: actions/checkout@v4
	- name: Pull musl
	run: \|
	git submodule update --init lib/musl
	- name: Restore LLVM source cache
	uses: actions/cache/restore@v4
	id: cache-llvm-source
	with:
	key: llvm-source-18-linux-nix-v1
	path: \|
	llvm-project/compiler-rt
	- name: Download LLVM source
	if: steps.cache-llvm-source.outputs.cache-hit != 'true'
	run: make llvm-source
	- name: Save LLVM source cache
	uses: actions/cache/save@v4
	if: steps.cache-llvm-source.outputs.cache-hit != 'true'
	with:
	key: ${{ steps.cache-llvm-source.outputs.cache-primary-key }}
	path: \|
	llvm-project/compiler-rt
	- uses: cachix/install-nix-action@v22
	- name: Test
	run: \|
	nix develop --ignore-environment --keep HOME --command bash -c "go install && ~/go/bin/tinygo version && ~/go/bin/tinygo build -o test ./testdata/cgo"

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