Added system_info.h header and syscall for get_system_info().

Added support functions in sem.h and port.h that return some stats.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@7289 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/port.h

@@ -12,6 +12,8 @@
 
 status_t port_init(kernel_args *ka);
 int delete_owned_ports(team_id owner);
+int32 port_max_ports(void);
+int32 port_used_ports(void);
 
 // temp: test
 void port_test(void);