error.
Do the real erroring out through a fatal error in pkgpath.mk (and set
PKGPATH to something less confusing than an empty variable). This
solves PR 5510 for real.
pwd -P, and we select the longest prefix from PORTSDIR_PATH.
This lets mystuff-like dirs get stripped from PKGPATH correctly, as long
as PORTSDIR_PATH is set correctly.