Version 2.25.1's libiberty can choke on some symbols. That was fixed in
2.27. As of writing, the last version is 2.30. Conservatively go with
2.28.1, which is the same major version (2.28) as what is currently in
Debian stable.
By default, wget prints dots every 1k bytes. This can render a
lot of output for large files. We switch to the "mega" style, which
makes each dot represent 64k, thus reducing output by up to 64x.
We also force the use of dot display. By default, it uses "bar"
which attempts to use terminal formatting if possible. Since most
of this code executes in CI and terminal control characters can
interfere with logged output, we force the use of "dot." (Although
wget appears to automatically switch to dot in TC today. But
consistency is good.)
MozReview-Commit-ID: IpTWJdcauTV
