The approach that was taken here was to add default values to the type
definitions rather than specify them whenever they are missing.
Now the only remaining warning is '-Wunused-parameter' which @jade said
is usually counterproductive and that we can just disable it:
https://git.lix.systems/lix-project/lix/issues/456#issuecomment-6617
So this change adds the flags '-Wall', '-Wextra' and
'-Wno-unused-parameter', so that all warnings are enabled except for
'-Wunused-parameter'.
Change-Id: Ic223a964d67ab429e8da804c0721ba5e25d53012
Lulu
43e79f4434