* Disable the lldb build for AArch64.
* Don't run the lldb tests on armhf (time out on the buildd).
* Rebuild for ocaml-4.01.
* Bring over Ubuntu changes from 3.3:
- Revert to using the static copy of libjsoncpp, since the shared
library lacks sane versioning, and this is only a few thousand
lines of cargo-culted code from a reasonably stagnant upstream.
- Drop lcov build-dep to avoid pulling it into main, due to its
being fundamentally incompatibe with our newer GCC versions.
* Don't run the lldb tests on armhf (time out on the buildd).
* Disable the lldb build for AArch64.
* Build-depend on gcc-multilib on amd64 and i386.
