为什么thread_local变量在这里从未初始化?

我正在通过速成课程C++遇到以下代码清单：

#include <cstdio>
struct Tracer {
Tracer(const char* name)
: name{ name } {
printf("%s constructed.n", name);
}
~Tracer() {
printf("%s destructed.n", name);
}
private:
const char* const name;
};
static Tracer t1{ "Static variable" };
thread_local Tracer t2{ "Thread-local variable" };
int main() {
printf("An");
Tracer t3{ "Automatic variable" };
printf("Bn");
const auto* t4 = new Tracer{ "Dynamic variable" };
printf("Cn");
}

这本书的作者声称我应该看到：

Static variable constructed.
Thread-local variable constructed.
A 
Automatic variable constructed.
B
Dynamic variable constructed.
C
Automatic variable destructed.
Thread-local variable destructed.
Static variable destructed.

这对我来说非常有意义。但是，当我在我的机器(MacOS，CLion，g ++(上运行它时，我看到以下内容：

Static variable constructed.
A
Automatic variable constructed.
B
Dynamic variable constructed.
C
Automatic variable destructed.
Static variable destructed.

为什么行为不同，t2变量会发生什么变化？