So I finally got JavaScriptCore to compile. In the end it wasn't too bad. I also built "testkjs", a console app used to test JavaScriptCore. I added various rules to my UserBuildConfig to populate the image with the files I need, but when I try to run testkjs I get the following error: runtime_loader: cannot open file libstdc++.r4.so Now I'm building on Linux so I'm not sure where the r4 came from. I see no libstc++.r4.so in the image. Here is how I build testkjs in my JavaScriptCore Jamfile: BinCommand testkjs : testkjs.cpp : JavaScriptCore.so ; Maybe it is something obvious, but I would appreciate any pointers on how to fix this. Regards, Ryan