Libtool support was needed to build shared library for libcacard.
Now there's no need to use libtool, and since the build system is
already complicated enough, we have a way to slightly de-complicate
it.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>