Add JSON output to pdbdump

[pombredanne]

I would like to run pdbdump and get structured and easily parsable output for use in tracecode-debug, a tool for an upcoming static analysis companion to https://github.com/nexB/tracecode-build

[jasonwhite]

Good idea. I originally wrote pdbdump so that I could diff two PDBs to help figure out why ducible might not be making a PDB bit-for-bit reproducible. JSON output would still be useful for this purpose.

If you or someone else wants to tackle this, I'd be happy to take a pull request for it. As it is now, I don't have the time for it.

[pombredanne]

Thanks. I may chip in when the needs becomes high then. Any preference for a JSON library? I would want to reuse existing code for that part.

[jasonwhite]

I haven't done much with JSON in C++, so I don't have much of a preference. The only thing is that it should be easy to integrate into the build. A header-only JSON library would be ideal.

With a quick search, I found this, which looks pretty good: https://github.com/nlohmann/json