Bug fixes:
  - Fix a severe virtual memory leak on Windows.  This regression was first
    released in 5.0.0.  (@Ignition, @j0t, @frederik-h, @davidtgoldblatt,
    @interwq)
  - Fix size 0 handling in posix_memalign().  This regression was first released
    in 5.2.0.  (@interwq)
  - Fix the prof_log unit test which may observe unexpected backtraces from
    compiler optimizations.  The test was first added in 5.2.0.  (@marxin,
    @gnzlbg, @interwq)
  - Fix the declaration of the extent_avail tree.  This regression was first
    released in 5.1.0.  (@zoulasc)
  - Fix an incorrect reference in jeprof.  This functionality was first released
    in 3.0.0.  (@prehistoric-penguin)
  - Fix an assertion on the deallocation fast-path.  This regression was first
    released in 5.2.0.  (@yinan1048576)
  - Fix the TLS_MODEL attribute in headers.  This regression was first released
    in 5.0.0.  (@zoulasc, @interwq)

Bug fixes (all only relevant to jemalloc 5.x):
  - Fix background thread index issues with max_background_threads.  (@djwatson,
    @interwq)
  - Fix stats output for opt.lg_extent_max_active_fit.  (@interwq)
  - Fix opt.prof_prefix initialization.  (@davidtgoldblatt)
  - Properly trigger decay on tcache destroy.  (@interwq, @amosbird)
???  - Fix tcache.flush.  (@interwq)
  - Detect whether explicit extent zero out is necessary with huge pages or
    custom extent hooks, which may change the purge semantics.  (@interwq)
  - Fix a side effect caused by extent_max_active_fit combined with decay-based
    purging, where freed extents can accumulate and not be reused for an
    extended period of time.  (@interwq, @mpghf)
???  - Fix a missing unlock on extent register error handling.  (@zoulasc)