cmd/cgo/internal/testsanitizers: add test case for #66427

The added program fails consistently with "signal handler spoils
errno" error under TSAN.

For #66427.

Change-Id: Id57b9e62aa30b273a1c793aecd86ec1f211062fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/581722
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/cgo/internal/testsanitizers/testdata/tsan15.go

@@ -0,0 +1,60 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// Test case for issue 66427.
+// Running under TSAN, this fails with "signal handler
+// spoils errno".
+
+/*
+#include <pthread.h>
+#include <signal.h>
+#include <stdlib.h>
+
+void go_callback();
+
+static void *thr(void *arg) {
+	int i;
+	for (i = 0; i < 10; i++)
+		go_callback();
+	return 0;
+}
+
+static void *sendthr(void *arg) {
+	pthread_t th = *(pthread_t*)arg;
+	while (1) {
+		int r = pthread_kill(th, SIGWINCH);
+		if (r < 0)
+			break;
+	}
+	return 0;
+}
+
+static void foo() {
+	pthread_t *th = malloc(sizeof(pthread_t));
+	pthread_t th2;
+	pthread_create(th, 0, thr, 0);
+	pthread_create(&th2, 0, sendthr, th);
+	pthread_join(*th, 0);
+}
+*/
+import "C"
+
+import (
+	"time"
+)
+
+//export go_callback
+func go_callback() {}
+
+func main() {
+	go func() {
+		for {
+			C.foo()
+		}
+	}()
+
+	time.Sleep(1000 * time.Millisecond)
+}

src/cmd/cgo/internal/testsanitizers/tsan_test.go

@@ -54,6 +54,7 @@ func TestTSAN(t *testing.T) {
 		{src: "tsan12.go", needsRuntime: true},
 		{src: "tsan13.go", needsRuntime: true},
 		{src: "tsan14.go", needsRuntime: true},
+		{src: "tsan15.go", needsRuntime: true},
 	}
 	for _, tc := range cases {
 		tc := tc