Merge branch 'ab/require-perl-5.8' into maint

* ab/require-perl-5.8:
  perl: use "use warnings" instead of -w
  perl: bump the required Perl version to 5.8 from 5.6.[21]

git-relink.perl

@@ -6,7 +6,7 @@
 #
 # Scan two git object-trees, and hardlink any common objects between them.
 
-use 5.006;
+use 5.008;
 use strict;
 use warnings;
 use Getopt::Long;