C++ solution

#include <iostream>
#define XYZZY

struct X
{
    X(const char* c) {}
};

void print(X)
{
    std::cout << "void print(const char* c);\n"
              << "#ifdef XYZZY\n"
              << "void print(const char* c) { std::cout << c; };\n"
              << "#endif\n";
}

int main()
{
    print("71E17-65E47-AD4D2-984F8\n");
}