Garbled output due to per-component parallelism

When building the `log` package with `cabal new-build` and GHC 7.8.4, I saw this:

```
[...]
[11 of 11] Compiling Log.Backend.ElasticSearch ( src/Log/Backend/ElasticSearch.hs, /home/refold/code/scrive/log/dist-newstyle/build/x86_64-linux/ghc-7.8.4/log-0.5.5/build/Log/Backend/ElasticSearch.o )
Configuring component test:log-test-integration from log-0.5.5
Configuring component test:log-test from log-0.5.5
Warning: The pWarning: aThcekage has a verspackage hiaosn a versriaonge fnor arange for da depenepdenedncye onn an interncaly on an in
ltibrarye:r nlaolg -any && ==0.5.5
, logl -any && ==i0.5.5. Tbhis rvaerrys:ion range has nloo
semangtic meani ng an-da ncyan be r emoved.&
& ==0.5.5, log -any && ==0.5.5. This version range has no
semantic meaning and can be removed.
Preprocessing test suite 'log-test' for log-0.5.5...
Preprocessing test suite 'log-test-integration' for log-0.5.5...
[1 of 2] Compiling Test.ElasticSearch ( test/Test/ElasticSearch.hs, /home/refold/code/scrive/log/dist-newstyle/build/x86_64-linux/ghc-7.8.4/log-0.5.5/c/log-test/build/log-test/log-test-tmp/Test/ElasticSearch.o )
[...]
```

Looks like a synchronisation fail somewhere.

Start by reproducing the garbled output with `cabal new-build` on the `log` package using GHC 7.8.4, focusing on the parallel component-build output. Trace the build's output synchronization and confirm that concurrent component messages remain readable without interleaving.

Written by the indexing model from the issue text.