MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

MFC r317284:
pmcstat(8); unsign some allocation variables and use reallocarray(3).

Use unsigned values in some internal variables that will be used during
allocation. The variables are used in reduced scope and have no chance of
becoming negative.

Provide bounds checking through reallocarray(3).

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

pmcstat: minor spelling fixes.

Mostly comments bur also a user-visible string.

MFC after: 2 weeks

More -Wmissing-variable-declarations fixes.

In addition to adding `static' where possible:

- bin/date: Move `retval' into extern.h to make it visible to date.c.
- bin/ed: Move globally used variables into ed.h.
- sbin/camcontrol: Move `verbose' into camcontrol.h and fix shadow warnings.
- usr.bin/calendar: Remove unneeded variables.
- usr.bin/chat: Make `line' local instead of global.
- usr.bin/elfdump: Comment out unneeded function.
- usr.bin/rlogin: Use _Noreturn instead of __dead2.
- usr.bin/tset: Pull `Ospeed' into extern.h.
- usr.sbin/mfiutil: Put global variables in mfiutil.h.
- usr.sbin/pkg: Remove unused `os_corres'.
- usr.sbin/quotaon, usr.sbin/repquota: Remove unused `qfname'.

- Support inlined location in calltree output.
In case of multiple level of inlining all the locations are flattened.
Require recent binutils/addr2line (head works or binutils from ports
with the right $PATH order).
- Multiple fixes in the calltree output (recursion case, ...)
- Fix the calltree top view that previously hide some shared nodes.

Tested with Kcachegrind(kdesdk4)/qcachegrind(head).

Sponsored by: NETASQ

Spelling fixes for usr.sbin/

Improve the chances of matching an outputted string with the line of code.

Remove duplicated header files

When an asm location cannot be resolved to a function the cost
will be spread as small value and then filtered by the threshold.
As a first step solution display the number of event that cannot
be resolved as a valid function location.

MFC after: 1week

Fix the calltree top view that incorrectly filter out some nodes.

MFC after: 1 week

Fix warnings found by Coverity.

Found with: Coverity Prevent(tm)
MFC after: 1 month

Rework the calltree top view by critical callchain.
The percentage show is the sum of the cost for the codepath.

MFC after: 1 week

Apply threshold filter to root node in calltree view.

MFC after: 3days

Improve "top" header by:
- Display sample received per PMCs (or merged PMCs).
- Display percentage vs all samples

Do not overflow the term in the case of multi-line display.

MFC after: 3days

Bug fixed:
- no display on serial terminal in top mode.
- display alignment for continuation string.
- correct invalid value used for display limit.

MFC after: 3 days

- Reorganize code in 'plugin' to share log processing.
- Kcachegrind (calltree) support with assembly/source
code mapping and call count estimator (-F).
- Top mode for calltree and callgraph plugin (-T).

MFC after: 1 month