Installer, Win: added helper for cross compile builders

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42768 4005530d-fff6-0310-9dd1-cebe43e6787f
Installer, Win: allow workaround for make2.8.0 issues (allow replacing make in final installer)

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42769 4005530d-fff6-0310-9dd1-cebe43e6787f