ticket:7747: fix gencmake.py, add more conditionals.

git-svn-id: http://source.icu-project.org/repos/icu/icu@36683 251d0590-4201-4cf1-90de-194747b24ca1
ticket:7747: update 2 files

git-svn-id: http://source.icu-project.org/repos/icu/icu@36684 251d0590-4201-4cf1-90de-194747b24ca1