This allows us to play with zero-copy and proto3 support for lite.
Unfortunately, it introduced some warnings, so deprecated warnings are
now ignored for benchmarks and interop-testing.
It doesn't appear that OS X is saving its cache yet, so this may not be
needed in the future, but for now we need OS X to avoid attempting to
use the Linux binaries.
The previous download link only worked for the most recent version. The
new form only works for old versions. That will encourage us not to use
the latest version, but for tests that's probably not a big deal.
We haven't noticed the breakage sooner because the build results are
cached.
Without the attributes, fc loses its mind a bit when comparing the
codegen output against the golden; the golden would have DOS newlines
(assuming default git configuration) and the generated code would have
Unix newlines.
The jenkins-pre script just reduces the amount of code is backed into
the jenkins project.