Add option to provide thirdparty dependencies externally #18

	name: Build

	on:
	push:
	# branches: [ main, develop ]
	pull_request:
	workflow_dispatch:

	# A workflow run is made up of one or more jobs that can run sequentially or in parallel
	jobs:
	build-linux:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- name: Install dependencies
	run: \|
	sudo apt-get update
	sudo apt-get install libgmp-dev libmpfr-dev libboost-all-dev libeigen3-dev libgeos-dev
	- name: Download CGAL
	run: \|
	wget https://github.com/CGAL/cgal/releases/download/v5.6.1/CGAL-5.6.1-library.tar.xz -P ${{ github.workspace }}
	cd ${{ github.workspace }}
	tar -xvf CGAL-5.6.1-library.tar.xz
	- name: Build
	run: \|
	mkdir build && cd build
	cmake .. -DCGAL_DIR=${{ github.workspace }}/CGAL-5.6.1 && make -j4

	build-macos:
	runs-on: macos-latest
	steps:
	- uses: actions/checkout@v4
	- name: Install dependencies
	run: \|
	brew update
	brew upgrade \|\| true
	brew install cmake boost cgal eigen geos
	- name: Build
	run: \|
	mkdir build && cd build
	cmake .. && make -j4

	build-windows:
	runs-on: windows-latest
	env:
	VCPKG_DEFAULT_TRIPLET: x64-windows
	VCPKG_INSTALLATION_ROOT: C:\vcpkg
	VCPKG_FEATURE_FLAGS: manifests
	steps:
	- uses: actions/checkout@v4
	- name: Build
	run: \|
	vcpkg install
	mkdir Release
	cd Release
	cmake .. -DCMAKE_TOOLCHAIN_FILE="$env:VCPKG_INSTALLATION_ROOT\scripts\buildsystems\vcpkg.cmake" -DVCPKG_TARGET_TRIPLET=x64-windows
	cmake --build . --parallel 4 --config Release

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