Error compiling libobjc2 - unwind.h not found

[Christopher Armstrong]

I've been wanting to try out the new libobjc2 runtime (discussed at http://etoileos.com/news/archive/2009/09/10/1744/) 
 that is in GNUstep SVN. I've compiled and installed gnustep-make  
from SVN, and now I'm trying to build libobjc2 but it fails with this  
error:

address@hidden:~/gnustep/libobjc2/trunk$ make
This is gnustep-make 2.2.0. Type 'make print-gnustep-make-help' for  
help.
Making all for library libobjc...
 Compiling file archive.c ...
 Compiling file class.c ...
 Compiling file encoding.c ...
 Compiling file exception.c ...
exception.c:27:10: fatal error: 'unwind.h' file not found
#include "unwind.h"
         ^
1 diagnostic generated.
make[2]: *** [obj/exception.c.o] Error 1
make[1]: *** [internal-library-all_] Error 2
make: *** [libobjc.all.library.variables] Error 2

I couldn't find unwind.h anywhere in the distribution, and it doesn't  
appear to be a public header on my system. Am I missing something  
before I try installing libobjc2? I have installed gnustep-make into a  
non-standard location, but I'm not sure how this would influence it.

Thanks
Chris

--------
Christopher Armstrong
address@hidden