I've done some searching in the past but couldn't find a liberally licensed embeddable web server for C or C++. That surprised me. I'm so used to having multiple good options in Java (such as Jetty) or built-in web servers say in Fan or Ruby.
Two options I've looked at are libmicrohttpd (but it's LGPL which causes too much bother) and lighttpd (but it's not really designed to have an embedded option so far as I can tell, which rather surprises me). Anything else out there?