Add support for linking against dependencies

[anderslanglands]

At the moment the bbl::bind() function just outputs the linking statements for the shim library, but not the target libraries that the shim itself links to.

This was done in cppmm already and means:

1. adding a dummy shared library target to the shim cmake
2. parsing the resulting cmake structure to extract the required linker arguments.

This work was already done in cppmm_build, so just needs porting over from there