extra-cmake-modules installs into versionned dir

[Alexander Neundorf]

On Sunday 19 February 2012, Stephen Kelly wrote:
> Alexander Neundorf wrote:
> > I want to be able to install multiple versions at the same time, right
> > from the start.
> 
> Is the reason for this recorded? Why would you want that? So that backward
> incompatible changes can be made between versions?

So that it is easy for people to do that.
There will be frequent releases, different packages may need different 
versions. If some package doesn't compile because of a different required 
version, they can simply install the new required version of ecm additionally.
Why shouldn't it be possible ?
I don't see a reason.

ecm will be something which can easily break the builds of any packages out 
there. We have to be very careful with it, and I'd say right from the start, 
so it doesn't turn into a mess before we even release it.

Builds should not break with
"unknown cmake function ecm_something()"
so the user doesn't know what's wrong, they should say
"found ecm 0.1.2, but required is 0.1.3"

Running into a cmake error is not a viable option as error handling.

Alex