Switches to a doubly-linked list for the free lists, to improve performance on perlbench in particular.  To make room for the prev pointer, adds a union to the chunk header to trade it off with fields only needed for live or delay-free chunks.
Switches to a doubly-linked list for the free lists, to improve performance
on perlbench in particular.  To make room for the prev pointer, adds a
union to the chunk header to trade it off with fields only needed for live
or delay-free chunks.

SVN-Revision: 1265

sigma-random/drmemory,code4bones/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,code4bones/drmemory,code4bones/drmemory,code4bones/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,code4bones/drmemory