CMake: scripts improvements


git-svn-id: svn://svn.code.sf.net/p/mediainfo/code/MediaInfoLib/trunk@6419 45c5ae6f-87cc-4fd0-92ee-e4f023fd80da
fixed compilation without AES

git-svn-id: svn://svn.code.sf.net/p/mediainfo/code/MediaInfoLib/trunk@6420 45c5ae6f-87cc-4fd0-92ee-e4f023fd80da