[BuildTools] Putting COIN projects `elsewhere'

[Lou Hafer]

Ted,

> It seems to me that there may be some simpler solutions to this issue at 
> play here. The easiest one is just to include all the COIN projects that 
> have Osi interfaces as externals. What would be the objection to this? 
> The download would be too big? It would take too long to compile?

    Size is certainly an issue.  Kassman was also commenting that in the
    build system that he's constrained to use, it's much easier to handle
    components individually.  Also, Externals is only an option if you're
    working from the svn repository. Third-party is needed if you're working
    from tarballs.

> If you are worried about the download being too big, then a simple 
> solution would be to set up the configure script to look for projects 
> like Cbc and SYMPHONY and build them if they are there---otherwise skip.

    True.  Could, and should, be done.  Cbc does this with DyLP.  I'll put
    it on my maintenance list for Osi.

> Then anyone wanting those projects could simply modify their externals 
> locally and those projects would automatically be included in the build. 
> Wouldn't that be easier than treating them as third party? I guess the 
> only problem might be compatibility of different version, but that will 
> be a problem in any case.

    I suspect that all of us developers have been doing exactly what you
    suggest --- modifying Externals and then doing some minor hacking of
    configure.ac.  But I'd still find it convenient to be able to test
    OsiFoo without having to put Foo's source tree into the Osi project
    bundle, given that I already have Foo built in another tree. If nothing
    else, it saves me time when I try to commit configuration changes,
    'cause I don't have to back out tweaks related to non-standard
    Externals.
    
    For non-developers, I suspect that the third-party style is more what
    they're used to using.

    What I'm aiming for, in the end, is a top-level configure.ac that will
    decide whether you have Foo as a source tree in the standard place
    (acquired via Externals, or whatever), or whether you have it as
    `third-party', or whether it's entirely absent.

							Lou