Don't pass literal strings when a char* is needed.

Perhaps IsUserNameValid() shouldn't need to modify its parameter; but
its test shouldn't pass it a const char* parameter as long as it
claims it does.  Turn the literals into initializers for non-const
arrays.
Warning-fix: use assert_true() in tests rather than assert().

In an NDEBUG build, assert() doesn't actually test the condition; but
the test should indeed be testing it, so assert_true() is more apt.
Also simplify a return.
Only mark parameter as unused when it isn't used.

CurrentZoneName()'s string parameter is only used when we
HAVE_GETZONEID; so only mark it as unused when that's not enabled.
Mark parameter as unused only when it isn't actually used.

Was marked as unused, but is used in an assertion.
Apply suitable #if-ery to the ARG_UNUSED.
warning-fix: Correct signature of SaveXmlCallback().

It's used as a SaveCallbackFn, so needs to accept a NewLineMode as
third parameter, even if it does ignore it.  It should also be a
static function (nothing outside its file uses it); and we may as well
simplify the #if-ery around it and its one caller.
Typo-fixes and a rephrase in HACKING.md

s/absued/abused/
s/indenpendent/independent/
Rewrote garbled line about keeping log messages atomic.
Warning-fix: eliminate uses of deprecated sprintf().

All in verify_databases.c; and clean up CreateTableColumns(), which
was one of the culprits.  It was also adding random extra amounts of
space to an allocation - "just in case" I suppose - thereby
obfuscating the actual amount of space needed.  Eliminated an
intermediate fixed-size buffer we didn't need (and any associated
truncation).  Avoid quadratic costs associated with repeatedly
traversing a string to find its end, at which to append.
Test for cf_null in bundlesequence being skipped

Redmine 6119
Skip cf_null entries in bundlesequence.

Fixes Redmine 6119
Indentation - whitespace-only change
Merge pull request #1978 from vohi/redmine/6119

Redmine/6119
Merge pull request #1966 from ediosyncratic/warning-fixes

Warning fixes
Don't reuse overspill from an early ps field as part of a later one.
Attempt to handle ps fields that extend right under next header.

See comments in commit.  Also deals with the case where one field
appears to extend right under the next's header, but it's really the
next extending left under the first's header.
Add a TODO about handling of tabs in ps output.

We can hope this is a non-issue; it only matters if some ps actually
does use tabs in its output.
Discovered a hidden complicator to VPSOPTS, sync'd with changes there.

In process_select.c, access to VPSOPTS is mediated via a function
GetProcessOptions() so as to implement a hack to omit the NLWP field
on Linux 2.4 (should probably be Linux < 2.4); naturally, its copy of
the options was out of sync with the copy (including nlwp) in
systype.c; so bring it in sync again and add a comment to VPSOPTS to
remind anyone changing the Linux entry there to make a matching change
in this second place.
Add a unit test for SplitProcLine().
Remove spurious cast, refine a comment.