32비트 컴파일러와 64비트 컴파일러에서 `int64_t`, `long int` 및 `long long int`의 동작이 다른 이유는 무엇입니까?

<code class="cpp">#include <iostream>
#include <cstdint>

template <typename T>
bool is_int64() { return false; }

template <>
bool is_int64<int64_t>() { return true; }

int main()
{
    std::cout << "int:\t" << is_int64<int>() << std::endl;
    std::cout << "int64_t:\t" << is_int64<int64_t>() << std::endl;
    std::cout << "long int:\t" << is_int64<long int>() << std::endl;
    std::cout << "long long int:\t" << is_int64<long long int>() << std::endl;

    return 0;
}</code>

int:           0
int64_t:       1
long int:      0
long long int: 1

int:           0
int64_t:       1
long int:      1
long long int: 0

<code class="cpp">#if defined(__GNUC__) && (__WORDSIZE == 64)
template <>
bool is_int64<long long int>() { return true; }
#endif</code>

<code class="cpp">// C++11
template <typename T>
void same_type(T, T) {}

void foo()
{
    long int x;
    long long int y;
    same_type(x, y); // Will now compile successfully
}</code>