[brassybadger]

After a quick glance it also seems that newer versions of SpiderMonkey only offer a C++ API, so you can't embed it anymore into C apps without some glue code. I checked out jsapi.h in SpiderMonkey24 - maybe some trick is needed to use SM from C?

[pcwalton]

New versions of SpiderMonkey only expose a C++ API (because of exact rooting), but we'll need to fix that at some point as part of Servo since this is a hazard for Rust. Currently we use an old version of SpiderMonkey for this reason.