[build2] Installation Configuration Variables: Absolute Paths, Config Location, Version Tag

[Boris Kolpackov]

Markus Pawellek via users <users at build2.org> writes:

> > I agree config.install.etc=data_root/etc/ is a good idea and
> > I will go ahead and add it.
> 
> That is great. Thank you.

Ok, it's available in the staged toolchain.


> When installing two versions of the same application 'hello'
> what will be the installation path of their binaries?
> Maybe the following when using '/usr/local' as prefix?
> 
> /usr/local/bin/hello/0.1.0/hello
> /usr/local/bin/hello/0.2.0/hello

Another alternative would be /usr/local/bin/hello-X.Y.Z which
you can achieve with config.bin.exe.suffix=-X.Y.Z (though the
<version> substitution does not work there).


> On Linux, small variations of the following three alternatives
> seem to be the typical layout for multiple versions.
> Please correct me, if I am wrong here.
> 
> (1)
> /usr/local/bin/hello-0.1.0
> /usr/local/bin/hello-0.2.0
> /usr/local/bin/hello                   -> /usr/local/bin/hello-0.2.0
> 
> [...]
> 
> Does build2 support such layouts by automatically creating appropriate
> symbolic links when installing?

No, and I am not convinced it's build2's place even if it could.
Feels like this should be managed by the entity that decided to
support installation of multiple versions, such as, the distribution
package's build/install script.