Add support for OpenSSL 3 (and EL9/Debian 11/Ubuntu 22)
Allow tcpd/libwrap to be excluded from build when present on the system
Allow loading of full certificate chains
Change -u (connection issues return UNKNOWN) to include all SSL-layer failures.
Disable renegotiation and enforce server cipher order when using SSL
Verify that private keys match certificates when using SSL
FIXES
Fixed incorrect default for nasty_metachars in nrpe.cfg
Fixed incorrect help text for --use-adh
Fixed potential out-of-bound read when used with IPv6
Signed-off-by: Peter Müller <peter.mueller@ipfire.org>