[CMake] --graphviz and generator expressions

[Brad King]

On 06/05/2014 02:08 PM, Andrew Fuller wrote:
> After more investigation it appears --graphviz does handle generator
> expressions ... partially.  In particular it seems to get tripped
> up with $<JOIN:...>
[snip]
>     What is the proper way to generate the graph for a particular configuration?

The graphviz option has not been well maintained.  The notion of
one target depending on another is not as clear-cut these days
as it was when the graphviz option was first implemented.  The
graphviz option implementation still gets dependencies from some
outdated internal APIs that continue to exist only for some
backward compatibility features (policy OLD behaviors).

A non-trivial overhaul of the graphviz option implementation will
be needed to make it useful on projects using modern features.

-Brad