Cataclysm-dda: Minefields can spawn on roofs

[Ilysen]

Describe the bug
Roof tiles can have minefields on them. This happened with the home improvement superstore, so I'm not sure if it can happen on others.

To reproduce
Steps to reproduce the behavior:

1. Become a US general.
2. Go incredibly overboard with defending from criminals.
3. Have the Cataclysm happen.
4. Go to a home improvement superstore roof and admire your handiwork.

Expected behavior
For minefields to not spawn on rooftops.

Screenshots

Versions and configuration(please complete the following information):

• OS: Windows 10
• Game Version: 0.D-1549-g71b58ff
• Graphics version: Tiles
• Mods loaded:

  "dda",
  "aftershock",
  "makeshift",
  "More_Survival_Tools",
  "alt_map_key",
  "boats",
  "deoxymod",
  "despoiled",
  "no_npc_food",
  "filthy_morale",
  "manualbionicinstall",
  "safeautodoc",
  "novitamins",
  "No_Anthills",
  "nomolerats",
  "craftgp",
  "growable-pots"

(Despoiled just removes the spoilage timers on some foods.)

[curstwist]

That's a new one. I've seen artifacts, body sites also spawn up there.

[chaisawlajatang]

It may be a tactical solution to prevent airdrops. Someone placed mines on a possible drop location, some dirt for disguise and voila, a nasty surprise for enemy paratroopers!

[Ilysen]

I guess that explains the floating sign just to the right of the screenshots...!

[evil-toe-puppet]

Hi,
Describe the bug
i have a the same roof minefield stuff just on a Farm/ Green house roof with floating warning signs

Versions and configuration(please complete the following information):

OS: Windows 7
Game Version: 0.D-3611-g47d604b
Mods loaded:

[anothersimulacrum]

Minefields should only spawn at bridge entrances now (as of #31088), so unless you can confirm this on a more recent version, this issue should be closed.