Unused slabs which get recycled are no longer reinitialized from scratch if their chunk size matches what the allocator needed. If the chunk size matches, the list of available chunks is left unchanged, and just the various counters are reset.
Added __get_slab_stats() function.
Added support for global __slab_purge_threshold tuning variable.
Added a short test program for the slab allocator.
The malloc-test program was linked against the wrong object file in GNUmakefile.68k. Fixed.
