[cmake-developers] copy-if-changed in "make install"

[Brad King]

Alexander Neundorf wrote:
> http://bugs.kde.org/show_bug.cgi?id=132074

This should probably be submitted to CMake's bug tracker.

> Thomas complains that "make install" takes too long because cmake installs 
> only if the files differ. So he implemented in unsercmake a version which 
> doesn't compair the file contents, but only the size and the mtime.
> 
> This will undoubtedly work faster.
> It will also install files which were only touched but haven't changed. 
> 
> What do you think of this ?

The whole point of copy-if-different is that if the installed file has
not changed byte-for-byte then its timestamp should not change.  That
way user projects that build using the installed library/headers do not
have to rebuild more than necessary.

I've designed an md5sum-based scheme to do the copy-if-different for
installation in a much more efficient way.  It's on my todo list to
implement.

-Brad