configure: enable silent rules by default

configure: enable silent rules by default

The default build log is big and basically
unreadable.

Go the way of other build systems and do not
print compile commands by default. Verbose
output can always be enabled with make V=1.

Change-Id: Ib226079d1543209e08e5fdcf7344cd20850bea9d
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20231230142348.29108-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg27865.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>