scripts: On split use an actual regex instead of a literal string

Fixes BuiltinFunctions::ProhibitStringySplit.

Warned-by: perlcritic

scripts/Dpkg/Arch.pm

@@ -291,7 +291,7 @@ sub gnutriplet_to_debtriplet($)
 sub gnutriplet_to_multiarch($)
 {
     my ($gnu) = @_;
-    my ($cpu, $cdr) = split('-', $gnu, 2);
+    my ($cpu, $cdr) = split(/-/, $gnu, 2);
 
     if ($cpu =~ /^i[456]86$/) {
 	return "i386-$cdr";
@@ -339,7 +339,7 @@ sub debarch_to_debtriplet($)
     my $triplet = $debarch_to_debtriplet{$arch};
 
     if (defined($triplet)) {
-	return split('-', $triplet, 3);
+	return split(/-/, $triplet, 3);
     } else {
 	return;
     }

scripts/Dpkg/Vendor/Debian.pm

@@ -95,7 +95,7 @@ sub add_hardening_flags {
 
     # Adjust features based on Maintainer's desires.
     my $opts = Dpkg::BuildOptions->new(envvar => 'DEB_BUILD_MAINT_OPTIONS');
-    foreach my $feature (split(',', $opts->get('hardening') // '')) {
+    foreach my $feature (split(/,/, $opts->get('hardening') // '')) {
 	$feature = lc($feature);
 	if ($feature =~ s/^([+-])//) {
 	    my $value = ($1 eq '+') ? 1 : 0;

test/100_critic.t

@@ -37,6 +37,7 @@ my @policies = qw(
     BuiltinFunctions::ProhibitLvalueSubstr
     BuiltinFunctions::ProhibitReverseSortBlock
     BuiltinFunctions::ProhibitSleepViaSelect
+    BuiltinFunctions::ProhibitStringySplit
     BuiltinFunctions::ProhibitUniversalCan
     BuiltinFunctions::ProhibitUniversalIsa
     BuiltinFunctions::RequireGlobFunction