Allow running the script from any subdirectory

The script assumes it is running from the root of the repository. This change allows using the script from any subdirectory as well.

Author: uu1101

git-diff-blame

@@ -15,6 +15,11 @@ sub get_blame_prefix {
 	return $1;
 }
 
+$git_root = `git rev-parse --show-toplevel`;
+$git_root =~ s/^\s+//;
+$git_root =~ s/\s+$//;
+chdir($git_root) or die "$!";
+
 my ($oldrev, $newrev) = @ARGV;
 $oldrev ||= 'HEAD';
 if ($newrev) {