fix missing include #4

	name: build and test

	on:
	push:
	branches: main
	paths:
	- 'Makefile'
	- '*.hpp'
	- '*.cpp'
	- '.github/workflows/cpp.yaml'

	jobs:
	build-and-test:
	timeout-minutes: 15
	runs-on: ubuntu-22.04
	steps:
	- name: trust LLVM apt repositories
	run: wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key \| sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
	- name: add LLVM apt repositories
	run: \|
	sudo add-apt-repository --yes "deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-18 main"
	sudo add-apt-repository --yes "deb-src http://apt.llvm.org/jammy/ llvm-toolchain-jammy-18 main"
	- name: install llvm
	run: \|
	sudo apt update --yes
	sudo apt install --yes \
	clang-18 \
	libc++-18-dev \
	libc++abi-18-dev \
	lld-18
	- name: checkout ndvec repo
	uses: actions/checkout@v4
	- name: test
	run: make CXX=clang-18 test && ./test
	- name: main
	run: make CXX=clang-18 main && ./main \|\| [ "$?" -eq 50 ]

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