Make named a singleton process [RT#37908] Conflicts: bin/tests/system/conf.sh.in lib/dns/win32/libdns.def.in lib/isc/win32/file.c The merge also needed to update files in legacy and tcp system tests (newly introduced in master after branch was created) to introduce use of lockfile.

[master] add DSCP support 3535. [func] Add support for setting Differentiated Services Code Point (DSCP) values in named. Most configuration options which take a "port" option (e.g., listen-on, forwarders, also-notify, masters, notify-source, etc) can now also take a "dscp" option specifying a code point for use with outgoing traffic, if supported by the underlying OS. [RT #27596]