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.
