Laz-perf is a relatively "underground" library, and is not packaged
for many major distributions. Its also tiny and trivial to include with
the other external libraries.
This avoids requiring users who want point cloud support to have to
compile their own laz-perf
when dependancies are missing (libzstd, lazperf) to an explicit
WITH_EPT optional cmake switch which requires those dependancies
This makes it easier people to determine whether they have the
complete set of necessary dependancies to build Entwine point
cloud support, as cmake will show an error if they enable WITH_EPT
but don't have them...
