ld: symbol(s) not found for architecture arm64 on xcode in mac m1

Question

I have to implement a permutation in c++ and I get the error in the title after the operator overloading.

The operator overloading code is here:

template<size_t n>
bool operator<(const permutation<n>& perm1 , const permutation<n>& perm2){
    for(int i = 0; i < n ; i++){
        if(perm1.arr_[i] > perm2.arr_[i])
            return false;
        else if(perm1.arr_[i]<perm2.arr_[i]){
            return true;
        }
    }
    return false;
}
template<size_t n>
bool operator>(const permutation<n>& perm1 , const permutation<n>& perm2){
    return(perm1 < perm2);
}
template<size_t n>
bool operator==(const permutation<n>& perm1 , const permutation<n>& perm2){
    for(int i = 0; i < n ; i++){
        if(perm1.arr_[i] == perm2.arr_[i])
            return true;
    }
    return false;
}
template<size_t n>
bool operator!=(const permutation<n>& perm1 , const permutation<n>& perm2){
    return(perm1 == perm2);
}
template<size_t n>
bool operator<=(const permutation<n>& perm1 , const permutation<n>& perm2){
    for(int i = 0; i < n ; i++){
        if(perm1.arr_[i] >= perm2.arr_[i])
            return false;
    }
    return true;
}
template<size_t n>
bool operator>=(const permutation<n>& perm1 , const permutation<n>& perm2){
    for(int i = 0; i < n ; i++){
        if(perm1.arr_[i] <= perm2.arr_[i])
            return false;
    }
    return true;    
}

I get a buildtime error that says

Undefined symbols for architecture arm64:
  "operator<(permutation<5ul> const&, permutation<5ul> const&)", referenced from:
      _main in main.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I tried to use the fix from Undefined symbols for architecture arm64: Xcode 12 but I could not find a setting called "Parallelize Build" on Xcode. I have no clue on how I can fix this.