--- percona-toolkit-2.2.16/bin/pt-query-digest  2015-11-06 14:56:23.000000000 -0500
+++ percona-toolkit-2.2.20/bin/pt-query-digest  2016-12-06 17:01:51.000000000 -0500
@@ -2555,8 +2583,8 @@
    }
    return sprintf(
       $num =~ m/./ || $n
-         ? "%.${p}f%s"
-         : '%d',
+         ? '%1$.'.$p.'f%2$s'
+         : '%1$d',
       $num, $units[$n]);
 }

sudo apt-get install perl

git clone git@github.com:percona/percona-toolkit.git
cd percona-toolkit
perl Makefile.PL
make
make test
make install