[Cmake] out of source builds

[David Somers]

> > Trying to put all those commands in as a chain of custom build
> statements
> > seems overkill... so the ability to have a custom command run a
> series of
> > commands would be ideal :-)
>
> It's probably not too hard to implement.  Please add this as a feature
> request here:
>
> http://www.cmake.org/Bug

OK. Will add the request.

> I do not know when we will be able to get to this, but you will
> automatically be notified of progress when we do.

Great.

> You could write a program in C or C++ to do all these operations to
> generate the file instead of depending on programs like "sed" and "gawk"
> being installed on the machine and in the path.  Then just run this
> single program as the custom command.  If you add the executable as a
> dependency, then CMake will setup proper rules to make sure the
> generator executable is built before this custom rule is executed.

Yes, I could... its just that this project is for some third-party code
(cxref), so I just wanted to use it as sample project whilst I try to grok
Cmake and see how easy/hard it would be to mirgrate my build process to use
it. Plus, there are times when its just plain easier to run off a sequence
of sed/[g]awk/grep commands rather than write an c app. (I've recently
discovered - much to my own shock - that I quite like using things like sed
and awk to crunch files).

Cheers,

David