cc/gcc: add option to use system zlib

In some cases, it might be desirable to use the system zlib

Eg. because latest gcc seem to be totally borked when it comes
to multilib, and tries to build a multilib host zlib, when it
is *absolutely* *not* needed: we want mulitlib on the target,
not on the host! Sigh... :-(

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

python

import sys

sys.path.insert(0, '@@PREFIX@@/share/gcc-@@VERSION@@/python')

from libstdcxx.v6.printers import register_libstdcxx_printers

register_libstdcxx_printers (None)

end