Motivation / Problem

NFO spec and TTDP agree on this behavior:

• Industry variables 65 and 66 use the parameters as signed tile offset.
• Industry variable 66 and object variable 46 return no town zone, and use 32bit for the squared euclidian distance. (you can exceed 16bit already on a 256x256 map.)

OTTD contains various copy&paste mistakes that make it differ in the above items.

Description

The variables are fixed.
If a NewGRF would read the townzone from the euclidian-distance variable, it would break.
NewGRF written in NML are not affected (NML read the townzone from the correct variable).
NewGRF written in NFO (if there are any), are likely not affected, if the authors read the specs instead of OTTD source.

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker