Log message:
Drop superfluous PKG_DESTDIR_SUPPORT, "user-destdir" is default these days.
Mark packages that don't or might probably not have staged installation.

Log message:
Import polylib-5.22.5 as wip/polylib.

Polylib is a free C library for doing computations on polyhedra. The library is
operating on objects like vectors, matrices, lattices, polyhedra, Z-polyhedra,
unions of polyhedra and other intermediary structures. It provides functions
for all important operations on these structures