Disabling link with already installed libraries

[Bryan Blackburn]

On Thu, Oct 22, 2009 at 10:05:19PM +0200, vincent habchi said:
> From #22200 :
> 
> >thought it was worth noting that there is an additional problem.
> >no_atlas
> >variant has no effect if the atlas package is installed - numpy is
> >linked
> >against atlas regardless. This seemed to me a different issue than the
> >above, hence the two different tickets.
> 
> That's something I experienced also with other ports, notably when
> they are using Cmake. They find libraries in ${prefix}, wherever the
> user has enabled or disabled the corresponding option.
> 
> Being familiar with another build-from-source-framework, namely
> pkgsrc (wherefore I install my packages in /usr/pkg and not /opt) on
> NetBSD, it uses a more subtile process: all the dependencies are
> linked in a temporary repertory, and the traditional tools like gcc,
> g++, etc. are replaced by shell scripts that provide on the fly
> substitutions of library and include paths from standard directories
> to that temporary one. Therefore:
> 
> 1. When a dependency is not present, the package does not compile;
> 2. If an option flag that pulls a library in is not set, the library
> is not symlinked and the configure script does not find it, thereby
> enforcing the lack of dependency.
> 
> Is there any hope to get such a behavior in Macports?

Only if someone implements it.

Bryan


> 
> Vincent