wip
Revert "jemalloc: use $(AR), not `ar`"

This reverts commit ef436637ea02591c41b4898708f63bdf6e3f993c.
Revert "rt: make jemalloc header conform to android signature."

This reverts commit 2c7164595fd01f4a14763ed377aece1130de90c0.
Revert "Revert "Turn off jemalloc""

This reverts commit 0dceabda7f1049fd70d38cf61c80dd5148fdca4e.
core chase-lev appears to work?