Porting Bitcoin Core to CloudABI

Part of the reason this is feasible is that a number of dependencies were already ported to CloudABI -- from the blog post:

    leveldb
    boost (though boost::filesystem is problematic)
    libevent
    LibreSSL

Ed Schouten's blog post on porting LevelDB is at https://nuxi.nl/blog/2017/02/18/porting-leveldb-to-cloudabi....

This Bitcoin porting blog post provides some good insight on the challenges inherent in porting existing software to a strong sandbox.