Asio integration: link error in yield.hpp included in different cpp

[malirod]

In the file examples/asio/yield.hpp there is the line

thread_local yield_t yield{};

So if this yield.hpp included in two different cpp files then there will be link issue.

If existing code will be changed with following then issue is solved.

inline yield_t& this_yield() {
  thread_local yield_t yield;
  return yield;
}

[bitbugprime]

If you have C++17 it would be simpler to declare the global variable itself inline.