[Cmake] out of source builds

[Brad King]

David Somers wrote:
> For custom commands, is it possible to get it to issue multiple commands, or
> do I have to generate a batch/cmd file then execute that to do the multiple
> commands?

If there are intermediate outputs between each command you can chain 
together the custom commands by having each list the output of the 
previous command as a dependency.  That way the minimal amount of 
rebuilding will occur when something goes out of date.

-Brad