char *s21_strerror(int errnum) {
    char *error_message = NULL;
    if (errnum > -1 && errnum < 107) {  // Если ошибка существует
            error_message = (char*)sys_errlist[errnum];
    } else if (errnum > 106) {
        char unknown_error[30] = "Unknown error: ";
        char number[20];  // Для первода errnum в строку
        int count = 0;
        while (errnum / 10 != 0) {
            number[count++] = (errnum % 10) + '0';
            errnum /= 10;
        }
        number[count++] = errnum + '0';
        number[count] = '\0';
        char buf;
        for (int i = 0; i < count / 2; i++) {
            buf = number[i];
            number[i] = number[count - 1 - i];
            number[count- 1 - i] = buf;
        }
        s21_strcat(unknown_error, number);
        static char* result[1];
        result[0] = (char*)malloc(s21_strlen(unknown_error)*sizeof(char));
        for (s21_size_t i = 0; i < s21_strlen(unknown_error); i++){
            result[0][i] = unknown_error[i];
        }
        error_message = result[0];
        free(result[0]);  // Никаких утечек памяти в мою смену
    } else {
        errnum *= -1;
        char unknown_error[30] = "Unknown error: -";
        char number[20];  // Для первода errnum в строку
        int count = 0;
        while (errnum / 10 != 0) {
            number[count++] = (errnum % 10) + '0';
            errnum /= 10;
        }
        number[count++] = errnum + '0';
        number[count] = '\0';
        char buf;
        for (int i = 0; i < count / 2; i++) {
            buf = number[i];
            number[i] = number[count - 1 - i];
            number[count- 1 - i] = buf;
        }
        s21_strcat(unknown_error, number);
        static char* result[1];
        result[0] = (char*)malloc(s21_strlen(unknown_error)*sizeof(char));
        for (s21_size_t i = 0; i < s21_strlen(unknown_error); i++){
            result[0][i] = unknown_error[i];
        }
        error_message = result[0];
        free(result[0]);  // Никаких утечек памяти в мою смену
    }
    return error_message;
}