Improve general GNU hints, needed for GNU/Hurd.

Bug-Debian: http://bugs.debian.org/636609

With minor modifications to add Pino to AUTHORS.
Add GNU/Hurd hints for NDBM_File

currently, there are few tests failing because of a broken NDBM module;
using the same hints as used on Linux (given that apparently the cause
is the same) makes the following tests pass:
  t/op/dbm.t
  cpan/autodie/t/dbmopen.t
  cpan/Memoize/t/errors.t
  cpan/Memoize/t/tie_ndbm.t
  ext/NDBM_File/t/ndbm.t
  lib/AnyDBM_File.t

Dominic Hargreaves adds: Note that the original git commit log [what
you see above] lists some tests which aren't affected in blead.
Fix hang in ext/POSIX/t/sysconf.t on GNU/Hurd

while compiling perl 5.14.2 on GNU/Hurd, I ran into what it seems a
undefined POSIX behaviour in ext/POSIX/t/sysconf.t.

      my $fd = POSIX::open($fifo, O_RDWR)
      or skip("could not open $fifo ($!)", 3 * @path_consts_fifo);

according to the POSIX open()[1] about O_RDWR,
  The result is undefined if this flag is applied to a FIFO.
.... which is actually our case.
Apparently Linux and *FreeBSD (and maybe also OSes) accept this
behaviour, but on GNU/Hurd this causes the open() call to block
undefinitely. Given there's nothing done with the FIFO if not querying
{,f}pathconf() values, the proposed solution I attached is to change
the opening mode to "O_RDONLY | O_NONBLOCK".

[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html
enable LFS on GNU/Hurd

at the moment, perl is compiled on GNU/Hurd without large file support.
This, other than the lacking of support for files > 2 GB, causes the
failure in the t/op/stat.t test.
The failure in stat.t happens because of the following: when filtering
devices in /dev/* using grep {} with -b/-c, stat fails for large
devices such as /dev/hdX blocks, or /dev/zero chars (this latter case
should be an Hurd-specific issue, but shouldn't matter for this case),
hence the counts done with grep {} and the ones done filtering the
output of `ls' don't match.

The attached patch enables the LFS using the same way used on linux.sh;
about t/op/lfs.t, it gets skipped at the "kernel/fs not configured to
use large files?" check, although it correctly detects sparse files and
(at least by looking at the disk usage) allocates the 5GB (or so) file
created with system() in that test.
RT 64804: tainting with index() of a constant

Bug: http://rt.perl.org/rt3/Public/Bug/Display.html?id=64804
Bug-Debian: http://bugs.debian.org/291450
Origin: upstream, http://perl5.git.perl.org/perl.git/commit/3b36395d31cf0a2f3a017505cd0ea857a7acb5d1

At compile time, ck_index with a tainted constant set PL_tainted,
which remained on during the rest of compilation, tainting all other
constants.

Fix this by saving and restoring PL_tainted across the call to
fbm_compile, which is what sets PL_tainted.
properly propagate tainted errors

Backport af89892ed and 05a1a0145d by Tony Cook to 5.14

Bug: https://rt.perl.org/rt3/Public/Bug/Display.html?id=111654
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=663158
Close the eval "require $module" security hole in Digest->new($algorithm)

Also the filter was incomplete.

Bug-Debian: http://bugs.debian.org/644108