bison 3.4.2 complains when encountering '%pure-parser':
"warning: deprecated directive, use ‘%define api.pure’"
A quick google suggests this option has been around since at least
2012, maybe longer, so probably safe to replace.
Signed-off-by: Nicholas Sielicki <sielicki@yandex.com>
When a black-box item requests a specific footprint, we need to
read a file (<footprint>.fp) that contains the actual details
about that footprint. Support parse of that file and use the
loaded Element to generate the footprint for the item.