Integrate:

Integrate:
[ 26474]
Create a struct to use as the header with PERL_TRACK_MEMPOOL, so that
other information can be stored in it.

[ 26476]
If PERL_TRACK_MEMPOOL and PERL_POISON are in use, then scribble all
over memory to invalidate it just before free()ing it.

[ 26478]
For PERL_TRACK_MEMPOOL with PERL_POISON, Poison the end of any block
being shrunk in realloc()

[ 27084]
Enhance PERL_TRACK_MEMPOOL so that it also emulates the PerlHost
behaviour of freeing up all memory at thread exit. With this and
tools such as valgrind you will now get warnings as soon as you
read from the deallocated memory, rather than just a warning much
later about freeing to the wrong pool.

[ 27088]
Don't export PL_memory_debug_header to Win32 (and others) unless
PERL_TRACK_MEMPOOL is defined.

[ 27151]
With PERL_POISON defined, ensure freshly malloc()ed memory isn't zeros,
and when PERL_TRACK_MEMPOOL is also defined scribble on any extension
added by realloc().

[ 27343]
Subject: [PATCH] PERL_TRACK_MEMPOOL cripples environment after exit()
Message-ID: <20060226204721.00be2bff@r2d2>

[ 27396]
Don't free thread memory if PERL_DESTRUCT_LEVEL is set to a non-zero
value as we're probably hunting memory leaks then
p4raw-link: @27396 on //depot/perl: 55ef9aae2276249f1bc9d3c71e11acb54457a14a
p4raw-link: @27343 on //depot/perl: 22f43f2c71561997b91864c37ea97e2d3ad7e327
p4raw-link: @27151 on //depot/perl: 9a083ecf3183b31c0b60e9c5dac947cd40829810
p4raw-link: @27088 on //depot/perl: 02ca4724741a496db86d1f4591929ced61e3be44
p4raw-link: @27084 on //depot/perl: 7cb608b5fc09aa914d5f91646e40ed772b6bac01
p4raw-link: @26478 on //depot/perl: 2bee601c49fc5d1680112c819094102e0fe163b2
p4raw-link: @26476 on //depot/perl: cd1541b29232033fba1800a2ccd9ae38b4e1b8c3
p4raw-link: @26474 on //depot/perl: 731dcb42dfb65caf9942d70e5db009f245ecbefe

p4raw-id: //depot/maint-5.8/perl@29846
p4raw-integrated: from //depot/perl@27343 'merge in' miniperlmain.c
	(@27300..)
p4raw-integrated: from //depot/perl@27088 'merge in' makedef.pl
	(@26935..)
p4raw-integrated: from //depot/perl@27084 'edit in' util.c (@27065..)
	perl.c (@27077..) 'merge in' embedvar.h intrpvar.h perlapi.h
	(@27070..) sv.c (@27081..) pod/perltodo.pod (@27083..)
p4raw-edited: from //depot/perl@26474 'edit in' perl.h (@26447..)