MFC r326289:

Add basic tests for ctfconvert(1), fold(1) and rs(1)

Add basic command line parsing test coverage for these utilities. The tests
were automatically generated based on their man pages. These tests can be
expanded by hand for more thorough coverage. The aim is to generate very
basic amount of test coverage for all the utilities in the base system.

Tests generated via: https://github.com/shivansh/smoketestsuite/

Submitted by: shivansh
Reviewed by: asomers
Differential Revision: https://reviews.freebsd.org/D12424

MFC r314654:

cddl: normalize paths using SRCTOP-relative paths or :H when possible

This simplifies make logic/output

While here, remove bogus CFLAGS which look for headers in cddl/lib/libumem.
There aren't any source files there (just Makefiles)

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove stray DEBUG_FLAGS=-g that's been here since the initial import.

Convert to LIBADD

These CTF tools do not use anything from libctf, so no need to link with it.

Add man pages for the CTF tools.

Sponsored by: The FreeBSD Foundation

Remove manual .includes in cddl Makefiles

- Break the dependency on ../Makefile.inc for .PATH, and include
../Makefile.inc implicitly. This is required to ...
- Set WARNS?=6 in top-level Makefile.inc
- Remove now redundant WARNS settings, add WARNS?=0 where appropriate
- Remove redundant SHLIB_MAJOR overrides
- Use NO_MAN, not MK_MAN=no
- Remove redundant inclusion of bsd.own.mk
- Order Makefiles more according to style.Makefile(9)
- Reduce diff of cddl Makefiles against each other

No objection: pjd
Approved by: ed (co-mentor)

Fixed dependencies (make checkdpadd).

Add the DTrace build tools.