Log Message:
Update to 3.20160728. From the changelog:

* Explicitly remove current working directory from Perl's library
  search path, mitigating CVE-2016-1238 (see #588017)
* wrappers: allocate new environment dynamically, so we won't overrun
  the array if third-party plugins add multiple environment variables.
* Standards-Version: 3.9.8 (no changes required)