Guix pull fails on OS definition

[phodina]

Hi Guix,
Till now I've used custom channel for package definition only. However, I want 
to add to the channel also the definition for the operating system.

The problem is when I run =guix pull= the command fails. The reason is probaly 
due to the newly added configuration file which returns OS as a result. Without 
such a file the commands succeeds.

Is there a way to tell Guix not to evaulate such a file?

I looked into the Guix channel and the files are there with the extension tmpl. 
That however, didn't help.

In the gnu/system.scm file there is at the end expression with note:
"This is not super elegant but we can't pass SYSTEM and TARGET to 
'operating-system-derivation'

So is this the right direction to pursue and dig little bit deeper into the 
store-lift function?