Replace variable length array with malloc

Replace variable length array with malloc

Commit
https://github.com/OpenVPN/openvpn/commit/685e486e8b8f70c25f09590c24762ff73
4f94a51
introduced a variable length array. Although C99 supports that, MSVS 2013
still requires
size of array to be compiler time constant. As a fix, use malloc/free.

v2:
 Replace OPENSSL_malloc with gc_malloc

Signed-off-by: Lev Stipakov <lstipakov@gmail.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1445411606-13369-1-git-send-email-lstipakov@gmail.com>
URL: http://article.gmane.org/gmane.network.openvpn.devel/10344
Signed-off-by: Gert Doering <gert@greenie.muc.de>