Some build systems like Ninja offer support for emitting a compilation database (see http://clang.llvm.org/docs/JSONCompilationDatabase.html), which can be consumed by clang tools like clang-modernize and clang-tidy. We currently cannot easily use these tools because we cannot produce a compilation database.

We should write a scons tool that lets us emit a compilation database. Producing the database should not require actually compiling any files.