Add workaround for go-m1cpu compiler warnings

The testcontainers-go dependency uses go-m1cpu which generates harmless
CGO compiler warnings. Added:

1. .testcontainers-build-flags.sh: Script to suppress warnings
2. Updated TESTCONTAINERS_POC.md: Documentation about warnings
3. Note in testcontainers_helper.go: Explanation of warnings

These warnings don't affect functionality - they're from CGO code in
a third-party package. Users can suppress them with CGO_CFLAGS if desired.

Author: zph

.golangci.yml

@@ -0,0 +1,15 @@
+# GolangCI-Lint configuration
+# Suppress warnings from testcontainers dependencies
+
+linters-settings:
+  gci:
+    # Suppress warnings from third-party packages
+    skip-generated: true
+
+issues:
+  exclude-rules:
+    # Suppress warnings from go-m1cpu (testcontainers dependency)
+    - path: _test\.go
+      linters:
+        - gocritic
+      text: ".*go-m1cpu.*"

.testcontainers-build-flags.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+# Build flags to suppress warnings from testcontainers dependencies
+# Usage: source .testcontainers-build-flags.sh before building
+
+export CGO_CFLAGS="-Wno-gnu-folding-constant"

TESTCONTAINERS_POC.md

@@ -90,6 +90,26 @@ func TestAccDataSourceDatabases_WithTestcontainers(t *testing.T) {
 
 ## Troubleshooting
 
+### Compiler Warnings
+
+You may see warnings like:
+```
+warning: variable length array folded to constant array as an extension [-Wgnu-folding-constant]
+```
+
+These are harmless warnings from the `go-m1cpu` dependency (used by testcontainers-go). They don't affect functionality. To suppress them:
+
+```bash
+export CGO_CFLAGS="-Wno-gnu-folding-constant"
+go test -tags=testcontainers -v ./mysql/...
+```
+
+Or use the provided script:
+```bash
+source .testcontainers-build-flags.sh
+go test -tags=testcontainers -v ./mysql/...
+```
+
 ### Container Won't Start
 
 - Check Docker/Podman is running: `docker ps` or `podman ps`

mysql/testcontainers_helper.go

@@ -1,5 +1,9 @@
 // +build testcontainers
 
+// Suppress warnings from go-m1cpu dependency
+// These are harmless compiler warnings from CGO code in a third-party package
+//go:build testcontainers
+
 package mysql
 
 import (