Makes the NSS dependency explicit, and perform cleanup
Bump PORTREVISION

Before this patch if nss is installed when crony is built, there's a silent lib
dependency on nss, and if nss is subsequently uninstalled chrony breaks.

NSS is now turned on by default adding support for a number of more modern
hashing algorithms than md5.

Cleanup:

• --infodir is not a valid configure option (since 2.3 I think)
• USES=localbase instead of LDFLAGS
• add explicit --without-tomcrypt [1]
• add support for passing chronyd_flags to chronyd in rc.d script
• fix some hard-coded /usr/local in examples

PR: 217691
Submitted by: John Hein <z7dr6ut7gs@snkmail.com>
Approved by: Yonas Yanfa <yonas@fizk.net> (maintainer)