[boost] [thread] call_once regression or it is planed so?

Hi, With 1.54.0_beta1 following code fails to compile: #include <boost/thread/once.hpp> void init_host(int); void init_host(); boost::once_flag instance_flag = BOOST_ONCE_INIT; int main() { boost::call_once(&init_host, instance_flag); } In 1.53 it worked fine. Is that meant to be so and no workaround is possible, or is it a bug? -- Best regards, Antony Polukhin