error when compiling Haiku with gcc4

[diger]

hrev42345 gcc4

I cant build revision 42390 on gcc4.5.3 with error:

.....
C++ generated/objects/haiku/x86/release/add-ons/kernel/network/protocols/ipv6/ipv6.o
cc1plus: warnings being treated as errors
src/add-ons/kernel/network/protocols/ipv6/ipv6.cpp: In static member function 'static int32 FragmentPacket::NextOffset()':
src/add-ons/kernel/network/protocols/ipv6/ipv6.cpp:102: error: invalid access to non-static data member 'FragmentPacket::fNext'  of NULL object
src/add-ons/kernel/network/protocols/ipv6/ipv6.cpp:102: error: (perhaps the 'offsetof' macro was used incorrectly)
........

C++ compile the following test case:

#include <iostream>
#include <stddefs.h>

class _C {
  int f1;
  int f2;
};

int main(int, char**)
{
  std::cout << offsetof(_C, f1) << std::endl;
  return 0;
}

Failure occurred after hrev42382

[axeld]

Fixed in hrev42399.