on FreeBSD with gcc, no GC, standard runtime, I get:
Making all for tool make_strings...
Compiling file make_strings.m ...
In file included from ../../Source/./common.h:34,
from make_strings.m:23:
../../Headers/Foundation/NSZone.h:78: error: expected
specifier-qualifier-list before '__unsafe_unretained'
../../Headers/Foundation/NSZone.h:312: error: expected '=', ',', ';',
'asm' or '__attribute__' before 'void'
../../Headers/Foundation/NSZone.h:319: error: expected '=', ',', ';',
'asm' or '__attribute__' before 'void'
In file included from make_strings.m:25:
../../Headers/Foundation/NSAutoreleasePool.h:56: error: expected
specifier-qualifier-list before '__unsafe_unretained'
../../Headers/Foundation/NSAutoreleasePool.h:95: error: expected
specifier-qualifier-list before '__unsafe_unretained'
In file included from ../../Headers/Foundation/NSDictionary.h:30,
from make_strings.m:26:
../../Headers/Foundation/NSEnumerator.h:40: error: expected
specifier-qualifier-list before '__unsafe_unretained'
gmake[5]: *** [obj/make_strings.obj/make_strings.m.o] Error 1