JavaScriptCore (the engine from WebKit) also has a very simple C interface (and I've seen it embedded by people as a static library without serious difficulty).
FWIW, the only times I've seen it as a static library (and the only real place you need a static library) is on iOS (where it was actually extra-dubious and I'm surprised more people didn't point out the problems; specifically this was as part of one of those JavaScript app frameworks like Titanium, although I don't quite remember if it was specifically Titanium), and JavaScriptCore is now provided on the system by Apple as a public framework as of iOS 7. On any other platform you should have no trouble shipping it as a dynamically-linked library due to its simple C API.
There's a nice overview here: http://blog.bignerdranch.com/3784-javascriptcore-and-ios-7/