Log Message:
5.0.1:

This bugfix release fixes several issues, most of which are obscure enough that \ 
typical applications are not impacted.

Bug fixes:
Update decay->nunpurged before purging, in order to avoid potential update \ 
races and subsequent incorrect purging volume.
Only abort on dlsym(3) error if the failure impacts an enabled feature (lazy \ 
locking and/or background threads). This mitigates an initialization failure bug \ 
for which we still do not have a clear reproduction test case.
Modify tsd management so that it neither crashes nor leaks if a thread's only \ 
allocation activity is to call free() after TLS destructors have been executed. \ 
This behavior was observed when operating with GNU libc, and is unlikely to be \ 
an issue with other libc implementations.
Mask signals during background thread creation. This prevents signals from being \ 
inadvertently delivered to background threads.
Avoid inactivity checks within background threads, in order to prevent recursive \ 
mutex acquisition.
Fix extent_grow_retained() to use the specified hooks when the \ 
arena.<i>.extent_hooks mallctl is used to override the default hooks.
Add missing reentrancy support for custom extent hooks which allocate.
Post-fork(2), re-initialize the list of tcaches associated with each arena to \ 
contain no tcaches except the forking thread's.
Add missing post-fork(2) mutex reinitialization for extent_grow_mtx. This fixes \ 
potential deadlocks after fork(2).
Enforce minimum autoconf version (currently 2.68), since 2.63 is known to \ 
generate corrupt configure scripts.
Ensure that the configured page size (--with-lg-page) is no larger than the \ 
configured huge page size (--with-lg-hugepage).