fail deps.pl if submodules don't download properly
sigh
Don't give rPois- via Venom card or poison miscast to the poison immune

Messages are still mediocre here, but whatever.

The nonliving can still get the reduction if they're not already poison
immune, but arbitrary resistances around there are a headache and they're
already blocked from being poisoned.
Don't assume all spells are evoked.

LLLAAASSSTTTYYY
Remove an evil special case (#9281).

I think this was somehow re-enabled during the monster spell slot
rework; it's not needed any more, in any case, as monster digging is
handled differently.
Simplify (wheals)
Darken Out-of-LoS tiles a bit
Potion tiles
Clean up spl-book.cc a bit.

Use a map, and change "int" params to use the proper enum type. Whether
the latter is really a good thing is arguable, since it does mean adding
more casts in more places, but I think it adds clarity to the calls.
Add support for arbitrary-size fixedbooks.

Which requires some massive code improvements, thankfully. Unfortunately,
making randbooks (including vault-defined ones) >8 spells long takes a lot
more work to do.
Improve distortion and rebranding interaction (#9278).
Replace Potions of Confusion with Ambrosia

A new potion, inspired by the old food item. Causes confusion
and an Elixir-like HP & MP-regeneration effect. If the confusion
is cured or prevented, the regeneration goes away.

[Committer's note: tweaked a bunch of stuff.]
Restore Spider's sweet ambrosia

This reverts commit 24381c416777577198129986a9082a3d73d2224d.
Allow Cigotuvi's Embrace to be in the spellbook loot for Fleshworks

I put it in the randbook named after him that's sometimes
generated. Also added necromancy as a potential second school for
choosing the other random spells in this book.
More Ru cleanup
Stop the fountains of Olympus (zxc232)

Don't give everyone ambrosia, everywhere, forever.
Tweak ambrosia

Give the healing + mp even on the last turn of the effect.
Mark Ambrosia useless under divine stamina
Refactor potion.cc to be a map

...from potion enum to potion effects, in a roughly similar structure to
transform.cc, etc.

Adjust other files acordingly; banish many inappropriate uses of potion_effect
when not actually drinking potions.

[Committer's note: fixed some things, rewrote stuff, etc]
Improve ambrosia messenging

Always print the ending message, regardless of whether it ended
by confusion ending or simple timeout.