Removed unused library and added doc in demo.pro for library search path #648

	name: linux-builds

	on: [push]

	jobs:
	build:
	strategy:
	matrix:
	os: [ubuntu-20.04]

	runs-on: ${{ matrix.os }}

	steps:
	- uses: actions/checkout@v1
	- name: install qt
	run: \|
	sudo apt-get update --fix-missing
	sudo apt-get install qt5-default
	sudo apt-get install qtbase5-private-dev qtdeclarative5-dev
	- name: qmake
	run: qmake
	- name: make
	run: make -j4

	build_ubuntu_2204:
	runs-on: ubuntu-22.04
	steps:
	- uses: actions/checkout@v2
	- name: Cache Qt
	id: cache-qt-6-4
	uses: actions/cache@v1 # not v2!
	with:
	path: ../Qt/6.4.2
	key: ${{ runner.os }}-QtCache-Qt6-4

	- name: Install Qt
	uses: jurplel/install-qt-action@v2
	with:
	version: '6.4.2'
	host: 'linux'
	target: 'desktop'
	install-deps: true
	cached: ${{ steps.cache-qt-6-4.outputs.cache-hit }}
	setup-python: true
	tools: ''
	tools-only: false

	- name: Install needed xkbcommon symlink
	run: sudo apt-get install libxkbcommon-dev -y

	- name: Ubuntu and Qt version
	run: \|
	cat /etc/issue
	echo number of processors: $(nproc)
	qmake -v
	- name: qmake
	run: qmake
	- name: make
	run: make -j$(nproc)

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