named_condition_any does not appear to notify

I haven't been able to get named_condition_any objects to work on Linux with Boost 1.68.0. Below is code to replicate. When using a named_condition_any the child process will never receive the notification, when using just a named_condition the child process receives the notifications.

```c++
#include
#include
#include
#include

#include

#include
#include
#include

namespace ip = boost::interprocess;

int main()
{
typedef ip::named_mutex mutex_type;
//typedef ip::named_condition condition_type;
typedef ip::named_condition_any condition_type;

mutex_type::remove("test_mutex");
condition_type::remove("test_condition");

pid_t pid = fork();
if(pid == 0)
{ // parent process
mutex_type mutex(ip::open_or_create, "test_mutex");
condition_type condition(ip::open_or_create, "test_condition");

while(true)
{
std::this_thread::sleep_for(std::chrono::seconds(1));
std::cout << "signaling children" << std::endl;
condition.notify_all();
}
}
else if(pid > 0)
{ // child process
mutex_type mutex(ip::open_or_create, "test_mutex");
condition_type condition(ip::open_or_create, "test_condition");

while(true)
{
boost::posix_time::ptime wait_time(boost::get_system_time() +
boost::posix_time::seconds(10));
ip::scoped_lock lock(mutex);
if(condition.timed_wait(lock, wait_time))
std::cout << "got signal from parent" << std::endl;
else
std::cout << "timeout" << std::endl;
}
}
else
{
std::cout << "failed to fork: " << pid << std::endl;
return 1;
}

return 0;
}
```

Start with the reproducer and compile it on Linux against Boost 1.68.0. Compare the behavior and implementation paths for boost/interprocess/sync/named_condition_any.hpp and named_condition.hpp, then verify that the child receives notifications when named_condition_any is used, including timed waits.

Scritto dal modello di indicizzazione a partire dal testo della issue.