Fix zlib mingw compile error by adding "VERBATIM"
This will hopefully fix the following dashboard error: https://open.cdash.org/viewBuildError.php?buildid=4138037
System updates will be applied on Nov 25th between 7am and 9am, EST (UTC-05:00). This site will have intermittent downtime during that time.
This will hopefully fix the following dashboard error: https://open.cdash.org/viewBuildError.php?buildid=4138037