Summary:
Two issues in the previous code:
1. We'd just tack on `#compilation-database` so if there already are `#flavors`
in a Buck target then we get a malformed `#flavors#compilation-database`
instead of `#flavors,compilation-database`. There's already code to deal
with that for other flavors (`#infer-capture-all`), so extend and reuse that.
2. The code didn't work if there are spaces in target names (sigh). Harden the
code a bit so that it works. Unfortunately Buck doesn't escape spaces at all
in its `buck targets --show-output` output, so the parsing still relies on
there being no spaces in flavors to work correctly. Sample output:
```
$ buck targets --show-full-output //clang_compilation_database:Hel\ lo#compilation-database
Not using buckd because watchman isn't installed.
[+] PROCESSING BUCK FILES...0.1s [100%] 🐳 New buck daemon
//clang_compilation_database:Hel lo#compilation-database /home/jul/infer/infer/tests/build_systems/codetoanalyze/buck-out/gen/clang_compilation_database/__Hel lo#compilation-database.json
```
Also, some code in codetoanalyze/clang-compilation-database/ didn't compile, so
fix that.
Reviewed By: dulmarod
Differential Revision: D4714338
fbshipit-source-id: b8ae324
Jules Villard