Installer, win: fix cross compile with fpc 2.7.1

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42536 4005530d-fff6-0310-9dd1-cebe43e6787f
Installer, win: deal with : in filename

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42537 4005530d-fff6-0310-9dd1-cebe43e6787f