This changes the buildlink3.mk files to use an include guard for the
recursive include. The use of BUILDLINK_DEPTH, BUILDLINK_DEPENDS,
BUILDLINK_PACKAGES and BUILDLINK_ORDER is handled by a single new
variable BUILDLINK_TREE. Each buildlink3.mk file adds a pair of
enter/exit marker, which can be used to reconstruct the tree and
to determine first level includes. Avoiding := for large variables
(BUILDLINK_ORDER) speeds up parse time as += has linear complexity.
The include guard reduces system time by avoiding reading files over and
over again. For complex packages this reduces both %user and %sys time to
half of the former time.
PolicyKit is an application-level toolkit for defining and handling the
policy that allows unprivileged processes to speak to privileged processes:
It is a framework for centralizing the decision making process with respect
to granting access to privileged operations for unprivileged applications.
PolicyKit is specifically targeting applications in rich desktop environments
on multi-user UNIX-like operating systems. It does not imply or rely on any
exotic kernel features.
