Named libraries are similar to the work library, but they are not
written to implicitly, or imported implicitly. They are only brought
in by a "library" clause, the the packages within the library are
brought in by a "use" clause.
Build up a work library by writing a VHDL representation of the
package header into a source file. This representation needs to
be accurate enough that later invocations of vhdlpp can read them
with the VHDL parser.
Include the compiler infrastructure to vhdlpp for collecting the
file and line information and attaching it to entities and ports.
Make the parser store the file name during parse.
Create a libmisc library where I can put source files that are
used by multiple programs within the source tree.