[Freeciv-Dev] (PR#6218) meta-ticket: gen-terrain

["Jason Short" <jshort@xxxxxxxxxxxxxx>]

Eventually all hard-coded references to terrain types (T_ARCTIC, T_OCEAN,
etc.) should be removed.  All terrain information should be loaded from
the ruleset.

Currently this is in a comparable state to the hard-codedness of
improvements.  However fewer options are needed for terrain so less work
should be needed.

I think the first step is adding a 'flags' element to terrain.ruleset.
Some new flags have been proposed (HUTS and BARBARIANS), and many existing
ones need to be written.  But first we need the infrastructure.  This
should generally be modeled after the 'flags' in units.ruleset
(unittype.c).

I will take any patches toward this goal.

See also the "barbarians on the poles" and "is_ocean read from rulesets"
tickets.  Both are moving toward the overall goal, but are not doing so in
an elegant way.

jason