// http://golang.org/issue/17641.
static void callWithVarargs(void* dummy, ...) {
	va_list args;
	va_start(args, dummy);
	va_end(args);
}

// Signal handler for SIGSEGV on a C thread.
static void segvHandler(int signo, siginfo_t* info, void* ctxt) {
	sigset_t mask;
	int i;

	// Call an arbitrary function that requires the stack to be properly aligned.
	callWithVarargs("dummy arg", 3.1415);

	if (sigemptyset(&mask) < 0) {