member with constructor not allowed in anonymous aggregate

[Serge Crouzy <crouzy@xxxxxxxxxxxxxxxxxx>]

Hi all GCC Gurus -)

I'm having problems trying to port C++ code from windows (Visual Studio 
 C++ Express 2005) to Linux  Gcc 3.2.2.5 or 3.4.3.9.EL4

In constructs like :

union {
       struct {
              Mat33               orient;

where Mat33 is a user defined class of 3 by 3 matrices used to define a 
new c++ type, I get the following error with gcc on Linux (Intel P IV PC):

error: member Mat33 Transform::<anonymous union>::<anonymous 
struct>::orientation' with constructor not allowed in anonymous aggregate
error: member `Mat33 Transform::<anonymous
union>::<anonymous struct>::orientation' with constructor not allowed in 
union

The same lines compile all right on windows with VS

Any help to fix or work around this problem would be greatly appreciated  -)

Thanks a lot

Serge