config-msvc.h: indicate key material export support

config-msvc.h: indicate key material export support

MSVC build uses OpenSSL from vcpkg, which at the moment
is 1.1.1l. Key material export was added to 1.1.1, so it is safe
to indicate its support unconditionally.

2.5 does not have tls-ekm yet, but it has the generic keying material
exporter framework, which was only enabled in MinGW builds.  Fix.

Signed-off-by: Lev Stipakov <lev@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20211213135814.265-1-lstipakov@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23395.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>