[tbb-dev] Please check reproducibility of mac build with Snowflake (e084e83418)

I worked through some reproducibility issues and the mac build in the snowflake branch may be working. If someone has time, I would like them to test the build independently and see if they get the same hashes.

repo: https://git.torproject.org/user/dcf/tor-browser-bundle.git branch: snowflake commit: e084e834184d5ff61aef4c7f172ec883e266bdf7 hashes: https://people.torproject.org/~dcf/pt-bundle/snowflake/20170630-7.5a1-e084e8...

I only need the mac hashes ("./mkbundle-mac versions.alpha"). It takes about three hours for me. Here is more information on the mac build: https://bugs.torproject.org/19001#comment:32

If it builds reproducibly, then we are close to having a merge-ready branch for mac.