Add option to use fork-join-executor #45

	# Copyright (c) 2023 Hartmut Kaiser
	#
	# SPDX-License-Identifier: BSL-1.0
	# Distributed under the Boost Software License, Version 1.0. (See accompanying
	# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

	name: Linux CI (Debug)

	on:
	push:
	branches:
	- main
	pull_request:

	jobs:
	build:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v4

	- name: CCache
	uses: hendrikmuhs/ccache-action@v1.2.11
	with:
	key: ubuntu-latest-linux

	- name: Install llvm, clang 17
	shell: bash
	run: \|
	sudo apt purge llvm-16 clang-16 llvm-17 llvm-18 clang-17 clang-18 -y \|\| true
	wget https://apt.llvm.org/llvm.sh
	chmod +x llvm.sh
	sudo ./llvm.sh 17
	sudo apt install libclang-17-dev ccache -y

	- name: Build ChplX Debug
	shell: bash
	run: \|
	export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
	mkdir -p build && cd build
	cmake .. -DCMAKE_BUILD_TYPE=Debug \
	-DCHPL_HOME=$(realpath ../extern/chapel) \
	-DHPX_WITH_FETCH_BOOST=ON
	JOBS=$(( $(nproc) / 2 ))
	make -j$JOBS
	sudo make install
	make -j$JOBS tests.unit.backend_dir tests.unit.library_dir

	- name: CTest
	shell: bash
	run: \|
	cd build && ctest --output-on-failure

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