headers in ${BUILDLINK_DIR}, simply create BUILDLINK_CPPFLAGS.<pkg>
variables whose values are appended to CPPFLAGS, which are automatically
passed to the configure and build processes.
BUILDLINK_TRANSFORM.<pkg> has little use in buildlink2 since packages are
now told that the software may be found where it really is installed, not
in ${BUILDLINK_DIR} as was the case with buildlink1. Eventually, these
variables will be declared unsupported by buildlink2.
buildlink2.mk files back into the main trunk. This provides sufficient
buildlink2 infrastructure to start merging other packages from the
buildlink2 branch that have already been converted to use the buildlink2
framework.
