Installation of third party headers

[starseeker]

When building geogram in a minimalist configuration, I noticed that the lua third party headers are installed, even though lua is disabled for my build. That got me wondering - are the third party headers like lua and zlib necessary for client codes that are using the geogram headers, or are they only needed at build time?

It's not a major issue either way, but since I'm doing a minimalist build I thought it was worth asking if those headers are intended to be a part of the "minimalist" install or simply get installed automatically regardless of build settings - if the latter is the case, would a pull request trimming down which headers are installed be of interest?