complibs/libelf: use target ranlib

For portability, the right ranlib for the target must be passed to
libelf's configure.

Signed-off-by: "Titus von Boxberg" <titus@v9g.de>
(transplanted from e4a6fefcb0f5ecbcade3ae5edbe609560843aed1)

# Compute s390-specific values

CT_DoArchTupleValues() {

    # That's the only thing to override

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

        CT_TARGET_ARCH="s390x"

    fi

}