clear definition of build dependencies for sources shipped with JABAWS

It would be helpful if JABAWS developer documentation included a statement describing the minimum set of libraries that any JABAWS installation requires to be available on the system (e.g. libc/gcc/compilers/standard maths, etc).

This will allow developers adding new functionality to be able to identify which dependencies they need to embedd with JABAWS, and which ones they can assume will be available and need not incorporate.