[Insight-developers] Suggestion for ITK build/install process: Don't overwrite headers unless they change?

[Kent Williams]

This may actually be a CMake feature request, but I thought I'd bring it 
up here first.

When I am building an application using ITK, WrapITK, etc I do so 
against the CVS versions of all package. Each package gets configured, 
built, and installed as part of an overall make process.  For better or 
worse, this means I'm constantly running my own code against 'bleeding 
edge' versions of several packages.

One thing that's a little annoying about this system is this:  As an 
example, WrapITK depends on my installed ITK.  If a few things have 
changed in the ITK library -- even if it only touches a couple of files 
-- the entire set of libraries and header files are copied to the 
installation directory.  Then, if I build WrapITK, it generates and 
recompiles everything, because the modification times on all the ITK 
headers makes them newer than the object files in WrapITK.

It would be great in this context if CMake only copied files that were 
changed to the installation directory, so that any dependent libraries 
wouldn't get re-built unless there was a real change to ITK.

Or am I going about this multi-library build system thing all wrong?