Optimise gck variables
This introduces a few cleanups:
- moves GCK defaults out of
Makefile
intodefaults.mk
- removes some variables that are set since they are already covered by
CUSTOM_ENV
- the usage of
CUSTOM_ENV
is validated to ensure that it is present and evaluated - the main containers also have assigned default
hostname
to make it nicer
Edited by Kamil Trzciński (Back 2025-01-01)