jemalloc-4.0.0 test suite segfaults on aarch64

[Ingvar Hagelund]

I've started wrapping jemalloc-4.0.0 for fedora. aarch64 is now a target
arch for fedora. When sent to the arm builders, the unit/bitmap test
segfaults. Full log here:

http://arm.koji.fedoraproject.org//work/tasks/6832/3126832/build.log

Also note the vast amounts of "warning: left shift count is negative".

Unfortunately, I don't have access to aarch64 hardware myself, so
debugging and testing patches is a bit hard. But I can send scratch
builds to the Fedora arm builders and observe the results.

Ingvar