Please don't drag up old threads like this, as it's quite unlikely that the OP (or anyone relevant, as in this case) will respond. In this case, I've not reported the two posts from this year for splitting, as they'd be without context.
I'd assume you'd need to build FFmpeg from source and when configuring, you tell it where to find the required libraries (see "./configure --help", which will tell you the options you can use). You may also want to read the documentation
to see if there's anything useful there. I'm not sure whether (in general) it's possible to add shared libraries at runtime.