C/C で正規分布乱数を生成するにはどうすればよいですか?

#include <random>
#include <cmath>

// Generate a random number following a Gaussian distribution
double normal_rand() {
    static double z1;
    static bool ready = false;

    // If z1 is not ready, generate two uniform random numbers
    if (!ready) {
        double u1 = std::uniform_real_distribution<double>(0, 1)();
        double u2 = std::uniform_real_distribution<double>(0, 1)();
        z1 = std::sqrt(-2 * std::log(u1)) * std::cos(2 * M_PI * u2);
        ready = true;
    }

    // Return z1 and mark it as used
    ready = false;
    return z1;
}