Add a system include (geekosaur, #9363)
Ufetubus Reform

...but there are no penguins at the North Pole!?
Insult Reform
Make sure Santa gets mail forwarded from his old address.

Look for save chunks and bones under "Coc", not "Nor"; otherwise, if
a player saved in Coc and reloads for the holidays, they wind up in
a brand-new level, possibly embedded in rock or suspended over deep
water.

This change causes the same problem for people who saved in Nor, but
1. the end of the holidays will do that anyway; and 2. there are no
such saves on the servers at the moment.
Don't trap people in a minifort (theTower, #9328)

The default-mini_float behaviour doesn't actually connect up the
exit point that was found: it just verifies that at least one such
point was connected.  Still, that would have been a veto, but
currently deep water counts for the has_exits check.

This commit doesn't change either of those things, but works around
them by adding an explicit exit to the vault with @.
Prettify bolt_parent_init.
Add more speech for Asterion

Most of these lines are inspired by The House of Asterion.
Sorry that this isn't a Christmas easter egg.
Don't double numpad keys in SDL tiles.

We were getting both the keydown event for KP_2, and if numlock was
enabled a textinput event for "2".  Use a hack (stopping and restarting
text input---it works here) to suppress the textinput event when we
are already going to handle the keydown.

This likely screws up some input methods.
Treat keypad . as delete in SDL.

No other numpad key still cared about the numlock state.  And having
'.' on numpad isn't that helpful when KP_5 does that already.

The key is currently unbound.
Don't crash on item_slot=!1

Also, add a comment and demorgan an expression.

This will cause conflicts with branch ability_slot; resolve them in
favour of that branch.
Make never_decay chunks work (|amethyst)
Really make never_decay chunks work.
Fix several uses of delayed_decay, and document (#9312)