nsd: Update to 4.3.7

Changelog:
22 July 2021: Wouter
	- tag 4.3.7 release, with the fixes between rc1 and this release.

20 July 2021: Wouter
	- Fix typo in xfrd-tcp.c.

15 July 2021: Wouter
	- tag for 4.3.7rc1.
	- Fix compile of cookies on FreeBSD without IPv6.
	- Fix for loop initial declaration for nonc99 compiler.

14 July 2021: Wouter
	- Fix truncate test for EDNS COOKIE making one less RR is added.
	- Attempt to fix gcc11 warning.

13 July 2021: Willem
	- Fixes for child server processes getting out of sync with the
	  dnstap-collector process

13 July 2021: Willem
	- Interoperable DNS Cookies support as per RFC7873 and RFC9018

9 July 2021: Willem
	- Client side DNS Zone Transfer-over-TLS (XoT) support as per
	  draft-ietf-dprive-xfr-over-tls

29 June 2021: Willem
	- Fix #168: Buffer overflow in the dname_to_string() function

14 June 2021: Wouter
	- Update configure nonblocking test to use host.

25 May 2021: Wouter
	- Fix #179: log notice and server-count.

21 May 2021: Wouter
	- Test code has -q option for quiet output.

17 May 2021: Wouter
	- Update the ACX_CHECK_NONBLOCKING_BROKEN test for the configure
	  script.

7 May 2021: Wouter
	- Fix #176: please review Loglevel on missing zonefile.

6 May 2021: Wouter
	- Fix #174: NS Records below delegation are not ignored (nsd-checkzone
	  also does not raise any issue).

4 May 2021: Wouter
	- Fix SVCB sort call sizeof to be the size of the elements sorted.

29 April 2021: Tom
	- Implement Syntax of SVCB and HTTPS RR type as per draft-ietf-dnsop-svcb-https

13 April 2021: Wouter
	- Fix for #128: Skip over sendmmsg invalid argument when port is zero.
	- Fix #171: Invalid negative response (NSEC3) after IXFR.
	- Fix to make nsec3_chain_find_prev return NULL if one nsec3 left.
	- remove debug settings from unit test.

9 April 2021: Wouter
	- Fix for #170: Fix build warnings when IPv6 is disabled.
	- Fix #170: Disabled IPv6 and DNSTAP enabled triggers a build error.

30 March 2021: Wouter
	- Fix configure failure for enable systemd because of autoconf.
	- This became release 4.3.6, the repository continues for 4.3.7
	  in development.

29 March 2021: Wouter
	- Note unlisted changes in RELNOTES and prepare for 4.3.6rc1 tag.

29 March 2021: Willem
	- Per zone Access Control List for queries
	  with an allow-query: option.

24 March 2021: Wouter
	- Update acx_nlnetlabs.m4 to version 38, fix deprecation test.
	- Fix configure to use header checks with compile.
	- Fix warning about unused function log_addr.

18 March 2021: Tom
	- Add Extended DNS Errors RFC8914

15 March 2021: Wouter
	- Fix double config.h include in configlexer.c
	- Fix to remove configyyrename from makedist.sh and also
	  update the flex and bison rules there to add the "c_" prefix.

13 March 2021: Willem
	- Fix #154: TXT with parentheses fails in 4.3.5.
	- Align parsing of TXT elements with how bind does it.
	- A -p option to nsd-checkzone to print a successfully read zone.

12 March 2021: Wouter
	- Fix that wildcard is printed as a star instead of escaped, in
	  logs and in written zone files.
	- Fix unit test for wildcard printout change.

11 March 2021: Wouter
	- Fix #163: A TSIG noncompliance with RFC 2845.

9 March 2021: Willem
	- Enable configuring a control-interface by interface name.

19 February 2021: Wouter
	- Fix segfault on high verbosity for TLS channels with dnstap log
	  local address.

18 February 2021: Wouter
	- Fix #146 with #147: DNSTAP log the local address of the server
	  with the dnstap logs.

16 February 2021: Wouter
	- Man page documentation for dnstap options.

8 February 2021: Wouter
	- Fix AF_LOCAL compile error for Solaris.
	- Fix ifaddrs compile error for Solaris.
	- Fix ifaddrs.h compile error for Solaris.

4 February 2021: Wouter
	- Merge PR #153 from fobser: Repair -fno-common linker errors
	  automatically.
	- Fix uninitialized access of log_buf in error printout on apply ixfr.

26 January 2021: Wouter
	- Prevent a few more yacc clashes.


(ryoon)