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

Add META_MODE support.

Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.

Still need to add real targets under targets/ to build packages.

Differential Revision: D2796
Reviewed by: brooks imp

Reduce overlinking.
Because of libdtrace there is still a bit a overlinking but nothing we can deal
with easily

Make DTrace stuff compile with C99 standard.

Fix powerpc build:

Chase r270227 and compile lockstat with C99 standard.

Suggested by: bde

Convert the lockstat(1) man page to mdoc and make sure that it gets
installed. Additionally, remove Solaris-specific sections and references,
and replace example outputs with output from lockstat on FreeBSD, since
lockstat's output contains stack traces.

This change also removes some examples that don't seem to work properly on
FreeBSD. The examples should be re-added when lockstat is fixed.

Reported by: avg
MFC after: 1 week

lockstat(1) now depends on libutil and librtld_db.

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 OpenSolaris lockstat(1M) command. Requires the dtrace driver,
the lockstat provider, and the ksyms(4) pseudo driver kernel modules.

Approved by: gnn (mentor)