build: Add GitHub CI support for tests on ports

Add jobs for FreeBSD, NetBSD, OpenBSD, OmniOS (illumos) and macOS.

On NetBSD we install gsed, as the BSD sed does not like the
utf8toman.sed script.

We cannot enable Solaris, as the packages are very outdated, and
autopoint cannot find the archive.dir.tar.xz and fails to even
autoreconf. But the community based OmniOS based on illumos is a better
and more up-to-date replacement.

This uses the actions from <https://github.com/vmactions>.

.github/workflows/freebsd.yml

@@ -0,0 +1,26 @@
+name: FreeBSD test
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Test dpkg on FreeBSD
+    steps:
+    - uses: actions/checkout@v4
+    - name: Test in FreeBSD
+      id: test
+      uses: vmactions/freebsd-vm@v1
+      with:
+        usesh: true
+        copyback: false
+        prepare: |
+          pkg install -y pkgconf libtool autoconf automake gettext-tools gettext-runtime gtar patch gmake
+
+        run: |
+          echo "1.22.x" >.dist-version
+          echo "$GITHUB_SHA" >.dist-vcs-id
+          ./autogen && ./configure
+          gmake -j4 check TEST_PARALLEL=4

.github/workflows/macos.yml

@@ -0,0 +1,32 @@
+name: macOS test
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: macos-latest
+    name: Test dpkg on macOS
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Get build dependencies
+        run: |
+          brew update
+          brew install libtool autoconf automake gpatch libmd make
+
+      - name: Configure
+        env:
+          CPPFLAGS: -I/opt/homebrew/include
+          LDFLAGS: -L/opt/homebrew/lib
+        run: |
+          echo "1.22.x" >.dist-version
+          echo "$GITHUB_SHA" >.dist-vcs-id
+          ./autogen && ./configure
+
+      - name: Test
+        run: |
+          gmake -j4 check TEST_PARALLEL=4

.github/workflows/netbsd.yml

@@ -0,0 +1,26 @@
+name: NetBSD test
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Test dpkg on NetBSD
+    steps:
+    - uses: actions/checkout@v4
+    - name: Test in NetBSD
+      id: test
+      uses: vmactions/netbsd-vm@v1
+      with:
+        usesh: true
+        copyback: false
+        prepare: |
+          /usr/sbin/pkg_add pkgconf libtool autoconf automake gettext gtar gsed gcc13 patch gmake
+
+        run: |
+          echo "1.22.x" >.dist-version
+          echo "$GITHUB_SHA" >.dist-vcs-id
+          ./autogen && ./configure
+          gmake -j4 check TEST_PARALLEL=4

.github/workflows/omnios.yml

@@ -0,0 +1,30 @@
+name: OmniOS (illumos) test
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Test dpkg on OmniOS (illumos)
+    steps:
+    - uses: actions/checkout@v4
+    - name: Test in OmniOS (illumos)
+      id: test
+      uses: vmactions/omnios-vm@v1
+      env:
+        MAKE: gmake
+      with:
+        envs: 'MAKE'
+        usesh: true
+        copyback: false
+        prepare: |
+          pkg refresh
+          pkg install pkg-config libtool autoconf automake gnu-gettext gnu-tar gnu-patch gcc13 gnu-make
+
+        run: |
+          echo "1.22.x" >.dist-version
+          echo "$GITHUB_SHA" >.dist-vcs-id
+          ./autogen && ./configure
+          gmake -j4 check TEST_PARALLEL=4

.github/workflows/openbsd.yml

@@ -0,0 +1,33 @@
+name: OpenBSD test
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Test dpkg on OpenBSD
+    steps:
+    - uses: actions/checkout@v4
+    - name: Test in OpenBSD
+      id: test
+      uses: vmactions/openbsd-vm@v1
+      env:
+        AUTOCONF_VERSION: 2.72
+        AUTOMAKE_VERSION: 1.16
+        MAKE: gmake
+        LDFLAGS: -L/usr/local/lib
+        CPPFLAGS: -isystem /usr/local/include
+      with:
+        envs: 'AUTOCONF_VERSION AUTOMAKE_VERSION MAKE LDFLAGS CPPFLAGS'
+        usesh: true
+        copyback: false
+        prepare: |
+          pkg_add pkgconf libtool autoconf-2.72p0 automake-1.16.5 gettext-tools gettext-runtime gtar-1.35p0 gpatch gmake
+
+        run: |
+          echo "1.22.x" >.dist-version
+          echo "$GITHUB_SHA" >.dist-vcs-id
+          ./autogen && ./configure
+          gmake -j4 check TEST_PARALLEL=4