Porting/acknowledgements.pl: fix encoding of author names

Previously, running `Porting/acknowledgements.pl` or
`Porting/updateAUTHORS.pl --who` in a "UTF-8 by default" environment
(such as with `LANG=en_US.UTF-8 PERL_UNICODE=SL`) would mangle non-ASCII
characters in authors' names. (More specifically, it would double-encode
non-ASCII characters, so "Mannsåker" would render as "MannsÃ¥ker".)

Author: mauke

Porting/acknowledgements.pl

@@ -20,11 +20,16 @@ =head1 DESCRIPTION
 use strict;
 use warnings;
 use autodie;
+use Encode qw(decode_utf8);
 use POSIX qw(ceil);
 use Text::Wrap;
 use Time::Piece;
 use Time::Seconds;
 use version;
+
+binmode STDOUT, ':encoding(UTF-8)';
+binmode STDERR, ':encoding(UTF-8)';
+
 $Text::Wrap::columns = 77;
 
 my $since_until = shift;
@@ -162,6 +167,6 @@ sub commify {
 
 # returns a list of the authors
 sub authors {
-    return
+    return decode_utf8
         qx($^X Porting/updateAUTHORS.pl --who $since_until);
 }

Porting/updateAUTHORS.pl

@@ -65,6 +65,10 @@ package App::Porting::updateAUTHORS;
 );
 
 sub main {
+    # we encode_utf8() manually
+    binmode STDOUT;
+    binmode STDERR;
+
     local $Data::Dumper::Sortkeys= 1;
     my %opts= (
         authors_file    => "AUTHORS",