In CMake 3.0 the policy CMP0050 was introduced where it could be set to OLD to keep this behaviour while for NEW an error was raised.
Since CMake 3.5.2 a warning comes up when using the OLD behaviour and that it will be removed in a future version.
In FreeCAD we switched to the new behaviour now and removed the SOURCE signature from add_custom_command which affects the macros
fc_copy_sources, fc_target_copy_resource and fc_target_copy_resource_flat and their usage.
It's not possible any more to add files to a target by using the macros. Now a file must be added to the target before using the macros.
This commit fixes it for Arch, Draft, OpenSCAD, Material, Plot and Ship
