quadmath: try finding if only available as gcc internal library.
The miniperl skip in utf8cache.t was wrong.

But also test.pl needed fixing to be able to skip correctly.
t/lib/warnings/mg: Remove comment

The warning this refers to was removed (or moved to perl5db.pl) in
commit bbdae7b29367.
Fold t/lib/warnings/irs into mg

It took me a while to find these tests.  Most of these tests are arranged
by which C file they occur in.  (These warning tests were originally
added to make sure all warnings in all C files get tested.)
Make $/=-1 warning default like other dep warnings
Remove vmsish pragma from one-liners in Test::Simple's exit.t.

Awaiting upstream application at:

https://github.com/Test-More/test-more/pull/494

This was broken by a recent change that added double quotes around
the double quotes that were already there.

It also hasn't been working as intended for these tests for some
time as they manipulate the exit code directly in an END block,
and that sneaks by the effects of the pragma when run at compile
time.

This works:

  $ perl  -e "require vmsish; import vmsish 'hushed'; END {$? = 1};"

This (which is what the tests are doing) doesn't work:

  $ perl -Mvmsish=hushed -e "END {$? = 1};"
  %SYSTEM-F-ABORT, abort

So we'll just live with the noise from the exit messages.  They
don't seem to cause any trouble for the core test suite.
The 0d71ffa7 was quite sloppy with the sub-skips.
The skip count was all wrong.

Though that shows that acosh must be quite widely supported.
Helper function for 'close enough with epsilon'.
Deparse.t: To-do test for #115066
make debugging easier in memory allocator code in perl.c and util.c

-show intermediate values to make C debugging easier
-Perl_safesysfree overwrote var where with a different value, this caused
 alot of confusion for me of trying to hunt for a pointer from a stack
 trace with conditional breakpoints, so don't change var where in an
 unoptimized build
-in Perl_safesysrealloc and Perl_safesysmalloc provide 1 exit path, so
 the returned value is easily seen and BPed on unoptimized builds
Spell behaviour consistently in perlsub

We had six instances without U, and two with it.
Remove unused exit handler in vms/vms.c.

This code became obsolete in ff7adb5275976 and has just been
sitting there taking up space.
Silence spurious locale warnings

When testing the locales on the system, we don't want to be warned that
particular ones may not work well with Perl, as the point of the test is
to find and list the incompatibilities.

When looking for locales suitable for some purpose, we try every one
possible until we find one that matches what we're looking for.  This
may entail briefly switching into locales that aren't fully compatible
with Perl.  Again we don't want to be warned about such a locale.  We're
not using it for anything except to determine suitability anyway.
t/loc_tools.pl: Nits in comments, white-space only
t/loc_tools.pl: try code page 1252 locales

This makes sure this common locale on Windows doesn't get overlooked.
Revert the ‘return’ part of 6edcbed6

The gotos were jumping over initializations, causing
C+++threads+debugging to fail.
[perl #115066] Fix wrongly nested ‘use’ deparsing

B::Deparse was incorrectly putting ‘use’ statements and BEGIN blocks
inside other ‘use’ statements containing do-blocks, even if they were
originally outside.

Subroutines (except for cloned closures, which we don’t have to worry
about here) have an OUTSIDE pointer, pointing to the outer sub con-
taining the declaration of the sub in question.  So we can check that
to make sure we are putting the sub declaration in the right place.

Not only does this fix the reported case, but it also will allow
sequence numbers in inner subs to be reused by statements in outer
subs, which I may need in a future commit.
Put PL_cop_seqmax++ code in one spot
t/base/rs.t: Suppress warning