Компиляция, компоновка, линковка (undefined reference to.)

////////////options.hpp////////////////
#include <iostream>
#include <cmath>
#include <vector>
 
using namespace std;
 
class idholder {
private:
    static vector <int> idlist;
    static int nholders;
    static int lastid;
    int seekid(int id);
public:
    idholder();
    ~idholder();
    int getID();
    bool removeid(int id);
};
 
///////////////options.cpp//////////////////
#include "options.hpp"
 
int idholder::seekid(int id) {
    for(auto iterw = idlist.begin(), iterend = idlist.end();
            iterw != iterend;
            ++iterw) {
        if(*iterw == id)
            return distance(idholder::idlist.begin(), iterw);;
    }
    return -1;
};
 
int idholder::getID() {
    if(idlist.empty()) {
        lastid = 0;
        idlist.push_back(0);
        cout << " {{id taken : " << 0 << "}}";
        return 0;
    }
    for(int idtry = lastid; idtry >= IDHOLDER_IDMAX; ++idtry) {
        if(this->seekid(idtry) == -1) {
            idlist.push_back(idtry);
            lastid = idtry;
            cout << " {{id taken : " << idtry << "}}";
            return idtry;
        }
    }
    return -1;
};
 
bool idholder::removeid(int id) {
    cout << " {{id tryRemove : " << id << "}}";
    if(idlist.empty())
        return false;
    int index = seekid(id);
    if(index == -1)
        return false;
    auto iter = idlist.begin();
    iter += index;
    cout << " {{id removed : " << *iter << "}}";
    idlist.erase(iter);
    if (*iter < lastid){
        lastid = *iter;
    }
    return true;
}
 
idholder::~idholder() {
    --nholders;
    if(nholders == 0) {
        idlist.resize(0);
        lastid = 0;
    }
};
 
idholder::idholder() {
    ++nholders;
}