perlδ up to the present
[perl #96230] Stop s/$qr// from reusing last pattern

qr// should not be using the last-successful pattern, because it is
"(?^:)", not the empty pattern.  A stringified qr// does not use the
last-successful pattern.

This was fixed for m/$qr/ (and =~ qr//) in commit 7e31363783, but
s/$qr// was left out.
[perl #115260] Stop length($obj) from returning undef

When commit 9f621bb00 made length(undef) return undef, it also made it
return undef for objects with string overloading that returns undef.

But stringifying as undef is a contradiction in terms, and this makes
length inconsistent with defined, which returns true for such objects.

Changing this allows is to simplify pp_length, as we can now call
sv_len_utf8 on the argument unconditionally (except under the bytes
pragma).  sv_len_utf8 is now careful not to record caches on magical
or overloaded scalars (any non-PV, in fact).

Note that sv_len is now just a wrapper around SvPV_const, so we use
SvPV_const_nomg, as there is no equivalent sv_len_nomg.
regexp.h: Update comments

These comments should have been changed in commit
c74f6de970ef0f0eb8ba43b1840fde0cf5a45497, but were mistakenly omitted.
regexec.c: Change variable name

This actually is a pointer to the pattern string, not to a byte.
regen/regcharclass.pl: Change name of generated macro

This changes the macro isMULTI_CHAR_FOLD() (non-utf8 version) from just
generating ascii-range code points to generating the full Latin1 range.
However there are no such non-ASCII values, so the macro expansion is
unchanged.  By changing the name, it becomes clearer in future commits
that we aren't excluding things that we should be considering.
utf8.h: Add guard against recursive #include

A future commit will #include this from another header
regexec: Do less work on quantified UTF-8

Consider the regexes /A*B/ and /A*?B/ where A and B are arbitrary,
except that B begins with an EXACTish node.  Prior to this patch, as a
shortcut, the loop for accumulating A* would look for the first character
of B to help it decide if B is a possiblity for the next thing.  It did
not test for all of B unless testing showed that the next thing could be
the beginning of B.  If the target string was UTF-8, it converted each
new sequence of bytes to the code point they represented, and then did
the comparision.  This is a relative expensive process.

This commit avoids that conversion by just doing a memEQ at the current
input position.  To do this, it revamps S_setup_EXACTISH_ST_c1_c2() to
output the UTF-8 sequences to compare against.  The function also has
been tightened up so that there are fewer false positives.
regexec.c: Tighten loops in regrepeat()

regrepeat() is used to match some simple thing repeatedly in a row.  In
the case of EXACTFish nodes, it will repeat a single character (and its
fold).  Prior to this commit, it was using the full generality of
foldEQ_utf8() whenever the target was encoded in UTF-8.  This full
generality requires quite a bit of processing.  However, most
Unicode folds are of the simple variety containing just a character and
its upper- or lower-cased equivalent, and so the full generality of
foldEQ_utf8() is needed only comparatively infrequently.

This commit takes advantage of the newly added and enhanced
S_setup_EXACTISH_ST_c1_c2() to look at the character being repeated and
decide what level of generality is needed.  regrepeat() then uses a loop
that is only as complicated as needed.

This also adds some asserts that the nodes contain exactly 1 character
regexec.c: White-space only; no code changes

This indents a newly-formed block correctly
regcomp.c, regexec.c: Comments only; no code changes
regcomp.c: Pass NULL instead of &dummy to function

This saves the function from setting a throw-away value
regex: \R can match either 1 or 2 chars

Therefore it is not "simple", and should not be compiled as such,
causing things like the test added herein to fail.
regcomp.c: Silence compiler warning

I didn't notice that I had introduced this warning until now.
Used pad name lists for pad ids

I added pad IDs so that a pad could record which pad it closes over,
to avoid problems with closures closing over the wrong pad, resulting
in crashes or bizarre copies.  These pad IDs were shared between
clones of the same pad.

In commit 9ef8d56, for efficiency I made clones of the same closure
share the same pad name list.

It has just occurred to be that each padlist containing the same pad
name list also has the same pad ID, so we can just use the pad name
list itself as the ID.

This makes padlists 32 bits smaller and eliminates PL_pad_generation
from the interpreter struct.
perldelta for #115260
win32_freeenvironmentstrings: convert nonpublic exported function to macro

win32_freeenvironmentstrings was added in commit 4f46e52b008. It is not
documented as public api but is exported. Since it is nothing more than a
renaming of win32_free, replace it with a macro to win32_free. This saves
an entry in the export table, and the string name of the export from
perl517.dll. Also see
http://www.nntp.perl.org/group/perl.perl5.porters/2012/09/msg192954.html
avoid calling memset with a negative count

Poorly written perl code that allows an attacker to specify the count to
perl's 'x' string repeat operator can already cause a memory exhaustion
denial-of-service attack. A flaw in versions of perl before 5.15.5 can
escalate that into a heap buffer overrun; coupled with versions of glibc
before 2.16, it possibly allows the execution of arbitrary code.

The flaw addressed to this commit has been assigned identifier
CVE-2012-5195.
Remove unnecessary overrides in gnukfreebsd and gnuknetbsd hints.

hints/gnukfreebsd.sh and hints/gnuknetbsd.sh unconditionally
override Configure's values for ccdlflags and lddlflags, even though
the default Configure guesses should be correct for those systems.
Configure was altered in commit fb2e1bc0638d5a5d7ac552a79a71a996a5d604cc
(Perforce change 23909) to get the correct values, but later commit
46c947e8b9def6de34ac831834a3c290ab266515 (Perforce change 24017) included
these now-outdated hints file changes as part of importing a larger set
of patches from Debian.

This patch removes the unnecessary overrides.  Thanks to Niko Tyni for
digging up the history and supplying the hints/gnukfreebsd.sh patch.
add PERL_CALLCONV_NO_RET to perlhost.h's PerlProcExit and PerlProc_Exit

This gives noreturn to the 2 functions on Visual C Perl.