libc/uClibc: remove use of snapshots and specific date

We now have the ability to use a custom location, so supporting
snapshots or custom date is no longer needed. Let the user do the
required preparation in this case.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# Compute sparc-specific values

CT_DoArchTupleValues() {

    # That's the only thing to override

    if [ "${CT_ARCH_64}" = "y" ]; then

        CT_TARGET_ARCH="${CT_ARCH}64"

    fi

}