options.c: fix format security error when compiling without optimization

options.c: fix format security error when compiling without optimization

error: format not a string literal and no format arguments
[-Werror=format-security]
 2309 |     msg(M_USAGE, str);

Found by accident, since it only happens without optimization.
Seems the compiler can figure out that this is harmless when
thinking a bit harder about it. Fix anyway.

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20221228110752.34060-1-frank@lichtenheld.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg25848.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 24fc4ce25432a42170477f21133bb0f25a8a860d)