Why convert when you can simply embed?
https://code.google.com/p/v8/
"V8 can run standalone, or can be embedded into any C++ application."
Being embedded into a C++ application allows JavaScript to access any system that the C++ application has access to, eliminating the need to convert in the first place. I would limit what is has access to somewhat for security reasons though. Web-browsers are obviously the most prominent form of JavaScript being embedded in a C++ application. As implied by the name, JavaScript is a scripting language, not intended to be compiled into assembly/machine code as is C code.
