Add README, FUNDING, and CI files #449

	# https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions

	name: Main
	on:
	- push # branch or tag

	jobs:
	linux:
	strategy:
	fail-fast: false
	matrix:
	include:
	- job_name: ubuntu-x86_64 (testsuite)
	target: x86_64-linux-gnu
	- job_name: ubuntu-x86_64 (unittests)
	target: x86_64-linux-gnu
	- job_name: ubuntu-x86_64 (bootstrap)
	target: x86_64-linux-gnu
	bootstrap: enable
	- job_name: ubuntu-arm
	target: arm-linux-gnueabi
	- job_name: ubuntu-armhf
	target: arm-linux-gnueabihf
	- job_name: ubuntu-aarch64
	target: aarch64-linux-gnu
	- job_name: ubuntu-mips
	target: mips-linux-gnu
	- job_name: ubuntu-mips64el
	target: mips64el-linux-gnuabi64
	- job_name: ubuntu-mipsel
	target: mipsel-linux-gnu
	- job_name: ubuntu-powerpc64le
	target: powerpc64le-linux-gnu
	- job_name: ubuntu-systemz
	target: s390x-linux-gnu
	- job_name: ubuntu-sparc64
	target: sparc64-linux-gnu
	name: ${{ matrix.job_name }}
	runs-on: ubuntu-22.04
	env:
	GCC_CI_TARGET: ${{ matrix.target }}
	GCC_CI_BOOTSTRAP: ${{ matrix.bootstrap \|\| 'disable' }}
	steps:
	- uses: actions/checkout@v4
	with:
	fetch-depth: 10
	- name: Install dependencies
	run: ./buildci.sh installdeps
	- name: Configure gdc
	run: ./buildci.sh configure
	- name: Build gdc
	run: ./buildci.sh build
	- name: Run testsuite
	run: ${{ contains(matrix.job_name, 'testsuite') && './buildci.sh testsuite' \|\| 'echo disabled' }}
	- name: Run unittests
	run: ${{ contains(matrix.job_name, 'unittests') && './buildci.sh unittests' \|\| 'echo disabled' }}

Provide feedback