[github][actions] Add a new action to build LK, replacing travis-ci

Use the new github actions to replace the travis-ci builders which
seem to no longer work and are being removed.

This first stab is fairly rough, just matches the explicit matrix
that was in the travis-ci hooks, but at least gets back to a buildable
state again.

scripts/travis-build.sh

@@ -1,47 +0,0 @@
-#!/bin/sh
-
-# Copyright (c) 2014 Eren Türkay <turkay.eren@gmail.com>
-#
-# Permission is hereby granted, free of charge, to any person obtaining a
-# copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be included
-# in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-
-# This is a script for travis-ci that builds lk for different
-# architectures using different toolchains on travis-ci build machine.
-#
-# PROJECT and TOOLCHAIN are provided as environment variables. These
-# variables are specified in .travis.yml file.
-
-TOOLCHAIN_BASE_URL="http://newos.org/toolchains"
-TOOLCHAIN_SUFFIX="tar.xz"
-
-TOOLCHAIN_ADDRESS="$TOOLCHAIN_BASE_URL/$TOOLCHAIN.$TOOLCHAIN_SUFFIX"
-
-mkdir -p archives
-cd archives
-echo "Downloading toolchain $TOOLCHAIN from $TOOLCHAIN_ADDRESS"
-wget -v -N $TOOLCHAIN_ADDRESS || exit 1
-cd ..
-
-echo "Unpacking $TOOLCHAIN"
-tar xf archives/$TOOLCHAIN.$TOOLCHAIN_SUFFIX || exit 1
-export PATH=`pwd`/$TOOLCHAIN/bin:$PATH
-
-echo "Starting build '$PROJECT' with '$TOOLCHAIN'\n"
-./scripts/make-parallel $PROJECT