allow fcl files to be installed in a directory structure
By design, fcl files have been installed in a single directory. However, it could be useful to install them in a directory with a structure that mirrors the source code directory structure, similar to how headers are installed now.
The proposed solution would add a new option to the specification of fcldir in product_deps. We would add /tree to the directory specification. The default behavior would remain identical to current behavior.
Currently allowed options for fcldir:
fcldir <product_dir|fq_dir|-> [optional name]
We propose adding product_dir/tree and fq_dir/tree.