Make pod2html remove whitespace from literal blocks

This brings pod2html functionality similar to how Metacpan handles
whitespace

Author: scottchiefbaker

ext/Pod-Html/lib/Pod/Html.pm

@@ -367,6 +367,9 @@ sub pod2html {
 
     # set options for input parser
     my $parser = Pod::Simple::SimpleTree->new;
+    # Normalize whitespace indenting
+    $parser->strip_verbatim_indent(\&trim_leading_whitespace);
+
     $parser->codes_in_verbatim(0);
     $parser->accept_targets(qw(html HTML));
     $parser->no_errata_section(!$Poderrors); # note the inverse
@@ -842,4 +845,33 @@ sub relativize_url {
     return $rel_path;
 }
 
+# Remove any level of indentation (spaces or tabs) from each code block consistently
+# Borrowed from: https://metacpan.org/source/HAARG/MetaCPAN-Pod-XHTML-0.002001/lib/Pod/Simple/Role/StripVerbatimIndent.pm
+sub trim_leading_whitespace {
+    my ($para)    = @_;
+    my $tab_width = 4;
+
+    # Start by converting tabs to spaces
+    for my $line (@$para) {
+        # Count how many tabs on the beginnging of the line
+        my ($tabs)    = $line =~ /^(\t*)/;
+        my $tab_count = length($tabs);
+
+        # Remove all the tabs, and add them back as spaces
+        $line =~ s/^\t+//g;
+        $line = (" " x ($tab_count * $tab_width)) . $line;
+    }
+
+    # Find the line with the least amount of indent, as that's our "base"
+    my @indent_levels = (sort(map { $_ =~ /^( *)./mg } @$para));
+    my $indent        = $indent_levels[0] || "";
+
+    # Remove the "base" amount of indent from each line
+    foreach (@$para) {
+        $_ =~ s/^\Q$indent//mg
+    }
+
+    return;
+}
+
 1;