What libraries can be used when writing a contract in C++? What are the limitations? If I have a library I normally use and like, how do I compile it for use by contracts?
The code for Boost is in https://github.com/EOSIO/eosio.cdt/tree/master/libraries/boost
The main EOS library is eosiolib, and it uses Boost in action.hpp, dispatcher, datastream, etc.