At work I do multi-language development. One program has a mixture of C, C++ and Lua as a (more or less) static executable (Lua modules written in C and Lua are included in the executable). It was easy enough to add the steps to make to ensure the Lua files were recompiled (into an object file) if they changed. I'm bullish (skeptical) that this will be easy with an all-singing-all-dancing compiler/build/package program.