complibs/cloog: remove old CLooG/PPL versions

Those versions are no longer available upstream. They have purely and
simply disapeared, without leaving any trace of their mere existences.

Just keep the latest cloog-ppl-0.15.11, which still exists on the gcc
infra mirror (but for how long?)

Reported-by: Guillaume FLORENCE-COURTAND <gflorenc@laposte.net>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# Compute Alpha-specific values

CT_DoArchTupleValues () {

    # The architecture part of the tuple:

    CT_TARGET_ARCH="${CT_ARCH}${CT_ARCH_SUFFIX:-${CT_ARCH_ALPHA_VARIANT}}"

}