The motivation for this new DiagnosticConsumer is to provide a way for tools invoking the compiler
to get its diagnostics via a libclang interface, rather than textually parsing the compiler output.
This gives us flexibility to change the compiler's textual output, but have a structured data format
for clients to use to get the diagnostics via a stable API.
I have no tests for this, but llvm-bcanalyzer so far shows that the emitted file is well-formed.
More work to follow.
llvm-svn: 143259
Ted Kremenek