suspicious obj-c warnings [3.1]

[Aurelien]

Hi,

Worried about strange compiler warnings from gcc 3.1, I sent a message 
to the GNUstep mailing list reporting messages like the following:

/usr/local/bin/ld: warning: type and size of dynamic symbol 
'__objc_class_name_NSURL' are not defined
  or
Address.m:77: warning: '__objc_class_ref_NSObject' defined but not used

Some very competent person from the list replied the following:

"Fix the compiler ... seriously ... apparently it generates code that is 
technically wrong (though fine
on all known machines), so ld complains about it."

As I am myself incompetent in the field of compiler implementation ;-), 
I'm reporting this here...

Cheers,

Aurélien