This reworks the free store implementation in libc's malloc to use a
dlmalloc-style binary trie of circularly linked FIFO free lists. This
data structure can be maintained in logarithmic time, but it still
permits a relatively small implementation compared to other
logarithmic-time ordered maps.
The implementation doesn't do the various bitwise tricks or
optimizations used in actual dlmalloc; it instead optimizes for
(relative) readability and minimum code size. Specific optimization can
be added as necessary given future profiling.
c3207c31fc