#include<pthread.h>

typedef pthread_mutex_t __native_type;
#define __GTHREAD_MUTEX_INIT {0}

class timed_mutex
{
    // ...
    __native_type  _M_mutex;
public:
    timed_mutex() : _M_mutex({__GTHREAD_MUTEX_INIT}) { } 
    // ...
};

int main ()
{
  timed_mutex m;
}