CI: Move all remaining jobs from travis-ci to GHA

Some changes:

* Set HOME to /root, since github mounts its own HOME and 'wine'
  (because of permissions) and 'dub' (can't find packages) don't
  like that.
* Remove the seccomp option, doesn't seem to be needed.

Author: lazka

.github/workflows/os_comp.yml

@@ -27,3 +27,69 @@ jobs:
       # They are defined in the `env` section in each image.json. CI_ARGS should be set
       # via the `args` array ub the image.json
       run: bash -c 'source /ci/env_vars.sh; cd $GITHUB_WORKSPACE; ./run_tests.py $CI_ARGS'
+
+  eoan:
+    name: 'Ubuntu Eoan'
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        cfg:
+          - CC: 'gcc'
+            CXX: 'g++'
+          - MESON_ARGS: '--unity=on'
+            RUN_TESTS_ARGS: '--no-unittests'
+            CC: 'gcc'
+            CXX: 'g++'
+          - CC: 'clang'
+            CXX: 'clang++'
+          - MESON_ARGS: '--unity=on'
+            RUN_TESTS_ARGS: '--no-unittests'
+            CC: 'clang'
+            CXX: 'clang++'
+          - RUN_TESTS_ARGS: '--cross ubuntu-armhf.json --cross linux-mingw-w64-64bit.json'
+            MESON_RSP_THRESHOLD: '0'
+            CC: 'gcc'
+            CXX: 'g++'
+          - RUN_TESTS_ARGS: '--cross ubuntu-armhf.json --cross linux-mingw-w64-64bit.json'
+            MESON_ARGS: '--unity=on'
+            CC: 'gcc'
+            CXX: 'g++'
+
+    container:
+      image: mesonbuild/eoan
+      env:
+        MESON_RSP_THRESHOLD: ${{ matrix.cfg.MESON_RSP_THRESHOLD }}
+        MESON_ARGS: ${{ matrix.cfg.MESON_ARGS }}
+        RUN_TESTS_ARGS: ${{ matrix.cfg.RUN_TESTS_ARGS }}
+        CC: ${{ matrix.cfg.CC }}
+        CXX: ${{ matrix.cfg.CXX }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Run tests
+        shell: bash
+        run: |
+          export HOME=/root
+
+          export CC=$CC
+          export CXX=$CXX
+          export OBJC=$CC
+          export OBJCXX=$CXX
+          export PATH=$(pwd)/tools:$PATH
+          if test "$MESON_RSP_THRESHOLD" != ""
+          then
+            export MESON_RSP_THRESHOLD=$MESON_RSP_THRESHOLD
+          fi
+
+          source /ci/env_vars.sh
+
+          update-alternatives --set x86_64-w64-mingw32-gcc /usr/bin/x86_64-w64-mingw32-gcc-posix
+          update-alternatives --set x86_64-w64-mingw32-g++ /usr/bin/x86_64-w64-mingw32-g++-posix
+          update-alternatives --set i686-w64-mingw32-gcc   /usr/bin/i686-w64-mingw32-gcc-posix
+          update-alternatives --set i686-w64-mingw32-g++   /usr/bin/i686-w64-mingw32-g++-posix
+
+          ./run_tests.py $RUN_TESTS_ARGS -- $MESON_ARGS

.travis.yml

@@ -7,7 +7,6 @@ build system.
 #### Status
 
 [![PyPI](https://img.shields.io/pypi/v/meson.svg)](https://pypi.python.org/pypi/meson)
-[![Travis](https://travis-ci.org/mesonbuild/meson.svg?branch=master)](https://travis-ci.org/mesonbuild/meson)
 [![Build Status](https://dev.azure.com/jussi0947/jussi/_apis/build/status/mesonbuild.meson)](https://dev.azure.com/jussi0947/jussi/_build/latest?definitionId=1)
 [![Codecov](https://codecov.io/gh/mesonbuild/meson/coverage.svg?branch=master)](https://codecov.io/gh/mesonbuild/meson/branch/master)
 [![Code Quality: Python](https://img.shields.io/lgtm/grade/python/g/mesonbuild/meson.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/mesonbuild/meson/context:python)

README.md

@@ -362,8 +362,6 @@ Meson uses several continuous integration testing systems that have slightly
 different interfaces for indicating a commit should be skipped.
 
 Continuous integration systems currently used:
-- [Travis-CI](https://docs.travis-ci.com/user/customizing-the-build#skipping-a-build)
-  allows `[skip ci]` anywhere in the commit messages.
 - [Azure Pipelines](https://docs.microsoft.com/en-us/azure/devops/pipelines/scripts/git-commands?view=vsts&tabs=yaml#how-do-i-avoid-triggering-a-ci-build-when-the-script-pushes)
   allows `***NO_CI***` in the commit message.
 - [Sider](https://sider.review)

ci/travis_install.sh

@@ -5,13 +5,6 @@ the CI setup used for testing Meson itself. The Meson
 project uses multiple CI platforms for covering a wide
 range of target systems.
 
-## Travis CI
-
-The travis configuration file is the `.travis.yml` in the
-the project root. This platform tests cross compilation and
-unity builds on a [linux docker image](#docker-images) and
-on OSX.
-
 ## GitHub actions
 
 The configuration files for GitHub actions are located in