Bug#896827: perl: FTBFS on riscv64: t/re/fold_grind timeout

[Niko Tyni <ntyni@debian.org>]

Package: perl
Version: 5.26.2-2
X-Debbugs-Cc: debian-riscv@lists.debian.org

This package failed to build on riscv64.

  t/re/fold_grind ................................................ # Test process timed out - terminating
  FAILED--no leader found
  
  [...]
  
  Failed 1 test out of 2457, 99.96% okay.
  	re/fold_grind.t
  
  [...]
  
  Build needed 05:11:45, 350184k disk space

It looks to me like the buildd host is just too slow for this test.
>From the test:

    my $time_out_factor = $ENV{PERL_TEST_TIME_OUT_FACTOR} || 1;
    $time_out_factor = 1 if $time_out_factor < 1;

    watchdog(5 * 60 * $time_out_factor);

so the default timeout is five minutes but can be multiplied with
PERL_TEST_TIME_OUT_FACTOR in the environment.

AFAICS the build time of five hours is well above all the other
architectures, even m68k and sh4, and it's still less than half of
a successful build (we have to build perl three times with different
options, and run the test suite for two of those builds.)

@debian-riscv: I guess I can set PERL_TEST_TIME_OUT_FACTOR=2 for riscv64
in debian/rules or something like that, do you think that's sensible or
are the current riscv64 buildds going to get faster any time soon?
-- 
Niko Tyni   ntyni@debian.org