[CMake] Path to installed target

[Alexey Livshits]

> If the two "version" are needed you may build them in a single build.
>...
> but may be I'm missing something about your "2 versions"?
That's what I already do. The problem is, libv1 and libv2 should be
called libv.

> Alternatively, may be you can decide that your needed
> "temporary" install will always be in a fixed location relative to the
> build tree:
>
> ${CMAKE_BINARY_DIR}/tempinstall/
> then you always know where are installed the lib, executable etc...

Looks dirty, but this could be the solution :) Thank you.
-- 
BG,
Alexey