[Release-testers] [4.0.0 Release] Relase Candidate 1 has been tagged

[Hans Wennborg via Release-testers]

Dear testers,

4.0.0-rc1 was just tagged from the branch, with r292377.

There are still open merge requests and bugs, but I'd like to get the
testing started to see what issues come up.

Please build, test, and upload binaries to the sftp. Let me know how
it goes. I'll upload source, docs, and your binaries to the web site
once their ready.

Thanks,
Hans