doc: alternate signal stack setup for c-archive or c-shared builds (#2225)

Signed-off-by: Takeshi Yoneda <t.y.mathetake@gmail.com>

config.go

@@ -219,9 +219,18 @@ const (
 // part. wazero automatically performs ahead-of-time compilation as needed when
 // Runtime.CompileModule is invoked.
 //
-// Warning: This panics at runtime if the runtime.GOOS or runtime.GOARCH does not
+// # Warning
+//
+//   - This panics at runtime if the runtime.GOOS or runtime.GOARCH does not
 //     support compiler. Use NewRuntimeConfig to safely detect and fallback to
 //     NewRuntimeConfigInterpreter if needed.
+//
+//   - If you are using wazero in buildmode=c-archive or c-shared, make sure that you set up the alternate signal stack
+//     by using, e.g. `sigaltstack` combined with `SA_ONSTACK` flag on `sigaction` on Linux,
+//     before calling any api.Function. This is because the Go runtime does not set up the alternate signal stack
+//     for c-archive or c-shared modes, and wazero uses the different stack than the calling Goroutine.
+//     Hence, the signal handler might get invoked on the wazero's stack, which may cause a stack overflow.
+//     https://github.com/tetratelabs/wazero/blob/2092c0a879f30d49d7b37f333f4547574b8afe0d/internal/integration_test/fuzz/fuzz/tests/sigstack.rs#L19-L36
 func NewRuntimeConfigCompiler() RuntimeConfig {
 	ret := engineLessConfig.clone()
 	ret.engineKind = engineKindCompiler