feat: setup tests in the CI

.github/workflows/build.yml

@@ -0,0 +1,28 @@
+name: Build
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: bazelbuild/setup-bazelisk@v3
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build libpq
+        run: bazel build //:libpq
+      - name: Test C program
+        run: |
+            docker run --rm -d -p 5432:5432 -e POSTGRES_PASSWORD=postgres postgres:16.2-alpine &&
+                while !</dev/tcp/127.0.0.1/5432; do sleep 1; done &&
+                gcc examples/c/main.c -o main -l:bazel-bin/libpq.a &&
+                ./main

examples/c/main.c

@@ -0,0 +1,16 @@
+#include <libpq-fe.h>
+
+int main(int argc, char **argv)
+{
+    PGconn *conn = PQconnectdb("dbname=postgres password=postgres user=postgres host=localhost port=5432");
+    if (PQstatus(conn) != CONNECTION_OK)
+    {
+        fprintf(stderr, "connection to database failed: %s", PQerrorMessage(conn));
+
+        PQfinish(conn);
+        exit(1);
+    }
+
+    printf("connected to database\n");
+    PQfinish(conn);
+}