Compatibility breakage involved in upgrading to the MacOS-X 10.5 API

[Richard Frith-Macdonald]

In the 10.5 API almost all int or unsigned int parameters and return  
values are changed to NSInteger and NSUInteger.
The NSInteger and NSUInteger types are defined to be the same size as  
pointers.

I'm close to having this change complete and ready to commit for the  
GNUstep-base library, and wouldn't be worried about it but for the  
fact that it breaks compatibility on 64bit processors (though 32bit  
systems should be unaffected), since most 64bit processsors use 32bit  
integers and 64bit pointers, so the change means that most integers  
passed in the API will be twice as big on 64bit systems.

Obviously that breaks binary compatibility on 64bit systesm, but  
perhaps less obviously it also breaks source code compatibility in  
quite a few places (wherever the API changes from passing a pointer to  
a 32bit integer to now be passing a pointer to a 64bit integer), and  
will cause compiler warnings wherever we assign a 64bit integer to a  
32bit one.

Possibly there will also be issues with archived data (including gorm  
files).

So, how should we go about this?  Do we update GNUstep-base, accepting  
that parts of the gui and back libraries (and applications and data)  
will be broken by the change, then fix breakage as we find it, or do  
we attempt to do some sort of coordinated change?
If the latter, what would we try to coordinate, how would we manage  
it, and how would we test it?