new lightweight generics implemenation. (Newer MacOS X/iOS code assuming
the presence of the generics annotations can otherwise not be compiled with
GNUstep). This should be well-behaved under clang and gcc both.
Fix NSCache which was copying the cache keys when it really shouldn't
have. Added a few test cases for eviction behaviour.
Few smaller tweaks to avoid compiler warnings.
git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@39406 72102866-910b-0410-8b05-ffd578937521
