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.
Tested on NetBSD-current (i386 and amd64); support for
other architectures is in the works.
Currently this should work with:
ONLY_FOR_PLATFORM= FreeBSD-*-i386 NetBSD-*-i386 OpenBSD-*-i386
ONLY_FOR_PLATFORM+= FreeBSD-*-x86_64 NetBSD-*-x86_64 OpenBSD-*-x86_64
ONLY_FOR_PLATFORM+= DragonFly-i386-* DragonFly-x86_64-*
ONLY_FOR_PLATFORM+= Linux-*-* SunOS-*-*
