incompatibilities between base and libobjc2

[Eric Wasylishen]

Hi,
I've been trying to test libobjc2, and having some trouble. It looks like there 
are several compatibility issues between GNUstep base and libobjc2 that need to 
be fixed.

 - preface.h includes the sarray.h header, which is not present in libobjc2. It 
doesn't look like any of the sarray functions are used anywhere in GNUstep 
base, so this include can probably be removed (?)

 - NSObject.h uses a TypedStream class, not present in libobjc2. (for read: and 
write: methods which are commented out). It looks like the TypedStream stuff 
has been unused for a long time, maybe it can be removed from NSObject?

- libobjc2 lacks the encodings.h header. It looks like this needs to be added 
to expose the functions in libobjc2/encoding2.c for some parts of Foundation 
such as NSConnection. Also, old libobjc has encoding constants like "#define 
_C_INT 'i' " in objc/objc-api.h, and these constants aren't present in libobjc2

- GSObjCRuntime.m has include <objc/Protocol.h>, which isn't in libobjc2

- Source/GSPrivate.h uses "struct objc_category" and "Category"  which are not 
exposed by libobjc2. Not sure what to do for these..


Configure related:

 - In -base's configure script, the "checking whether objc really works" test 
fails because it expects the Object.h and NXConstantStr.h, which libobjc2 
lacks. The "-fconstant-string-class" test fails for the same reasons. Perhaps 
these tests should only be run if the test for libobjc2 fails (the one that 
tests if properties work)?

- the "config.forward.m" test (  checking for forwarding callback in runtime ) 
shouldn't be run on libobjc2 because libobjc2 doesnt' have __objc_msg_forward 
(it only has _forward2 and _forward3)

I may have missed a few other things, but this is a start. :-)

Cheers
Eric