Former-commit-id: 7fefc7b245bc1795bd67564bcc0a8a38d1ec121c
This reverts commit 36c1acc222d29e6e2dc9fc25362e4faa471111bd.
The original jemalloc source tree was modified to: 1. Remove the configure error that prevents nested builds. 2. Insert the Redis private Jemalloc API in order to allow the Redis fragmentation function to work.