sub check_version {
  my ($perl, $module) = @_;
  my @inc = `$perl -le "print for \@INC"`;
  chomp @inc;
  (my $file = "$module.pm") =~ s{::}{/}g;
  ($file) = grep -e, map { "$_/$file" } @inc;
  return undef
    unless $file;
  my $version = MM->parse_version($file);
  eval $version;
}