build fix

osdep/OSUtils.cpp

@@ -37,7 +37,7 @@ static clock_serv_t _machGetRealtimeClock() noexcept
 	host_get_clock_service(mach_host_self(),CALENDAR_CLOCK,&c);
 	return c;
 }
-static clock_serv_t s_machRealtimeClock = _machGetRealtimeClock();
+clock_serv_t OSUtils::s_machRealtimeClock = _machGetRealtimeClock();
 #endif
 
 unsigned int OSUtils::ztsnprintf(char *buf,unsigned int len,const char *fmt,...)