Revert "porting/podcheck corrections."

This reverts commit f6a6501216dee24e251d4482bd3a1f6daf4ac0da.

The fix seems wrong and is causing podcheck.t test failures, and (for my
system at least), reverting it removes those errors and doesn't create new
errors. Whatever was originally causing podcheck errors needs to be fixed,
rather than trying to mask it.
pat_advanced.t: Add tests

I almost broke this, so adding a precautionary test.
regcomp.c: Properly indent
Fix comment references to removed rexex ops

Commit 3018b823898645e44b8c37c70ac5c6302b031381 removed the regular
expression operations (regnodes) that these comments refer to, replacing
them with different ones.  Update the comments to be accurate
Perl_instr() implement with libc equivalent.

C89 libc contains the strstr() function that does the same thing as
instr().  Convert to use it under the assumption that it is faster than
our code, and is less for us to maintain.  Because early versions of
Lunix libc had a bug when the 'little' argument was NULL (fixed in late
1994), check for that explicitly.  If we were willing to ignore issues
with such old libc versions, or if we had a Configure probe that tested
for the bug, we could replace the macro instr() completely with a call
to strstr().

The memmem() GNU extension does the same thing as Perl_ninstr().  It
however has bugs in much later libc versions.  A Configure probe could
be written to see if it is usable.
Add regcomp.c warning checks to t/porting/diag.t.

 * Support regcomp.c ckWARN and vWARN macros
 * Update pod/perldiag.pod for fixes discovered with new checks
 * Allow t/porting/diag.t to match printfs with flags more liberally
Update HTTP-Tiny to CPAN version 0.025

  [DELTA]

  0.025     2012-12-26 12:09:43 America/New_York

    [ADDED]

    - Agent string appends default if it ends in a space, just like LWP
      [Chris Weyl]
Update Scalar-List-Utils to CPAN version 1.27

  [DELTA]

  1.26_001 -- Sun Dec 23 15:58

    * Fix multicall refcount bug RT#80646
regen/embed.pl: Add sanity test for entries

A void returning function should not be required to have its return
value tested.
regcomp.c: Don't iterate while changing an inversion list

This adds functions to prevent accidental (or deliberate) iteration over
an inversion list while it is being modified.  This is to catch
development errors, and in production builds, the asserts() are likely
no-ops
regcomp.c: Reword comment

To more accurately reflect newer code
regcomp.c: Handle edge case in inversion list max

The function _invlist_max() cannot currently be called on an inversion
list that was compiled in (via a C language array), because this edge
case is not considered.  I don't think current code ever does call this
function on this case, but that could inadvertently easily change.
regcomp.c: typo in comment
regcomp.c: Add #undef

The #defines in the first part of the file are #undef'd to try to keep
anything from inadvertently leaking into the 2nd part; this one was
omitted.
regcomp.c: Clean up ANYOF_CLASS handling.

The ANYOF_CLASS flag is used in ANYOF nodes (for [bracketed] and the
synthetic start class) only when matching something like \w, [:punct:]
etc., under /l (locale).  It should not be set unless /l is specified.
However, it was always getting set for the synthetic start class.  This
commit fixes that.  The previous code was masking errors in which it was
being tested for unnecessarily, and for much of the 5.17 series, the
synthetic start class was always set to test for locale, which was a
waste of cpu when no locale was specified.
regcomp.c: Remove unnecessary flag setting

The function cl_anything() sets things up so that the synthetic start
class parameter will match any character.  But this flag doesn't
contribute to that, as it sets things to match under certain conditions
only, and the characters it matches already match by the other actions
of the routine (the ANYOF_BITMAP_SETALL just above).
Free up regex ANYOF bit.

This uses a regnode type, of which we have many available, to free up
a bit in the ANYOF regnode flag field, of which we have none, and are
trying to have the same bit do double duty.  This will enable us to
remove some of that double duty in the next commit.
regcomp.h: Split two ANYOF flag bits

This essentially reverts 8b27d3db700fc2fce268e3d78e221a16ccaca2e8
and causes ANYOF nodes that are in locale but don't match things like \w
to have a smaller node size.
regcomp.c, regcomp.h: White-space, comment only

No code changes
Add new regnode for synthetic start class

This creates a regnode specifically for the synthetic start class, which
is a type of ANYOF node.  The flag bit previously used to denote this is
removed.  This paves the way for this bit to be freed up, but first the
other use of this bit must also be removed, which will be done in the
next commit.

There are now three ANYOF-type regnodes.  This one should be called only
in one place in regexec.c.  The other special one is ANYOF_WARN_SUPER.
A synthetic start class node should not do any warning, so there is no
issue of having something need to be both types.