This line in CMakeLists.txt causes trouble in recent cmake versions

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>
Separate pharo-vm into pharo-vm-core and pharo-vm-desktop + add libcairo2

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>
Let the user decide when he wants source or binary build

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>