Resolve link source to absolute path to minimize bad links

mklinks

 use strict;
 use warnings;
 use Getopt::Long;
+use File::Spec;
 
 sub usage { print STDERR "usage: $0: DOTROOT [PREFIX]\n"; exit 1; }
 
     my @dirs = `ls $dotroot`;
     foreach my $dir (@dirs) {
         chomp $dir;
-        my $source = "$dotroot/$dir";
+        my $source = File::Spec->rel2abs("$dotroot/$dir");
         my $target = "$prefix/.$dir";
         `mkdir -p $prefix`;
         if (-e $target) {