[CMake] Parallel builds do not work correctly when using "cmake -E copy" to copy files

[Bill Hoffman]

Alan W. Irwin wrote:

> My obvious next step is to try and make a simple CMake example that 
> reliably
> reproduces the bug, but this is such an important bug (at least for those
> with access to multiprocessors who want to use parallel builds) that I
> thought the above result was worth reporting immediately since it tends to
> point the finger at something CMake is doing rather than some bug in GNU
> make.
> 

We use -j N builds all the time at Kitware for VTK, ParaView and CMake. 
  It is however, possible to create input to CMake that will not work in 
a parallel environment.   A simple example would be the best way to 
figure out if there is a way around the issue you are having.  One thing 
you might want to look at is the add_dependancy command, and make sure 
that your custom targets are built in some order.  From your email, I am 
not exactly sure what targets are involved and what files are created at 
what time.

-Bill