Add tools/check_header.sh to check whether headers are self-contained

Author: hebasto

.github/workflows/ci.yml

@@ -738,6 +738,18 @@ jobs:
             g++ -Werror include/*.h
             clang -Werror -x c++-header include/*.h
 
+  headers:
+    name: "Self-contained headers"
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Test script
+        run: |
+          ./tools/check_header.sh src/field.h
+
   sage:
     name: "SageMath prover"
     runs-on: ubuntu-latest

tools/check_header.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+set -u
+
+for header in "$@"; do
+    source_file=${header%.h}.c
+    object_file=${header%.h}.o
+    mv "$header" "$source_file"
+    gcc -c "$source_file" -o "$object_file"
+    exit_code=$?
+    mv "$source_file" "$header"
+    if [ $exit_code -ne 0 ]; then
+        exit $exit_code
+    fi
+    echo "$header... OK"
+done