Initial GitHub Actions CI

This only builds the driver on Ubuntu. macOS and Windows, as well
as starting the LUW Docker container are TODO.

Author: NattyNarwhal

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: Build and Test
+on: [push, pull_request]
+jobs:
+  # XXX: macOS, Windows
+  ubuntu:
+    strategy:
+      matrix:
+          version: ['7.3', '7.4', '8.0', '8.1']
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Cache DB2 library
+        id: cache-clidriver
+        uses: actions/cache@v2
+        with:
+          path: clidriver
+          key: ${{ runner.os }}-clidriver
+      - name: Install DB2 library
+        if: steps.cache-clidriver.outputs.cache-hit != 'true'
+        run: |
+          wget https://public.dhe.ibm.com/ibmdl/export/pub/software/data/db2/drivers/odbc_cli/linuxx64_odbc_cli.tar.gz
+          tar xvzf linuxx64_odbc_cli.tar.gz
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{matrix.version}}
+          extensions: pdo
+      - name: Build PDO_IBM
+        run: |
+          phpize
+          ./configure --with-pdo-ibm=$PWD/clidriver
+          make
+      # XXX: No tests until DB2 Docker container is set up (see Travis)
+      #- name: Test dbase
+      #  run: make test TESTS=tests