Add workflow to check we have copyright headers with SPDX

.github/workflows/build-and-test.yml

@@ -10,7 +10,7 @@ permissions:
   contents: read
 
 jobs:
-  tycho-build:
+  build:
     runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4

.github/workflows/check-copyright-headers.yml

@@ -0,0 +1,18 @@
+name: Check copyright headers
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+permissions:
+  contents: read
+
+jobs:
+  check-licenses:
+    runs-on: ubuntu-22.04
+    steps:
+    - uses: actions/checkout@v4
+    - name: Check headers
+      run: ./check-copyright-headers.sh

check-license-headers.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+FIND=find
+if which gfind >/dev/null; then
+  FIND=gfind
+fi
+
+$FIND -name '*.java' | (while read f; do
+  if ! fgrep -q "SPDX-License-Identifier" "$f"; then
+    echo "File $f does not have a license header"
+    exit 1
+  fi
+done)