New monster spell: Control Winds

This spell allows the caster to continously manipulate the winds to
aid them and their allies. It is a self-enchant that will act
continuously for a decent number of turns after being cast, with the
following effects:

Firstly, it will immediately extinguish any forest fires in LoS of
the caster (both acting as a fire suppressor against the player's
actions as well as stray lightning bolts of the caster's own)

Secondly, it will blow clouds away from the caster. The path taken
by them is primarily direct repulsion from the caster, but with
three caveats:

a) A cloud will never be blown onto an ally. Alternate paths will be
   used instead, where possible.
b) A cloud currently engulfing a hostile will not be moved at all.
c) If there is no possible path to move a cloud engulfing an ally,
   instead greatly reduce that cloud's remaning duration.

This will allow spriggan air mages to stop starting raging forest
fires in their own home, prevent the player from doing likewise, and
generally provide protection for others against cloud spells, which
spriggans are highly vulnerable to.

1 files changed, 2 insertions, 0 deletions

diff --git a/crawl-ref/source/spl-clouds.h b/crawl-ref/source/spl-clouds.h
index b94578fe5f..d1b7c0c3e1 100644
--- a/crawl-ref/source/spl-clouds.h
+++ b/crawl-ref/source/spl-clouds.h
@@ -22,4 +22,6 @@ spret_type cast_corpse_rot(bool fail);
 void corpse_rot(actor* caster);
 
 int holy_flames(monster* caster, actor* defender);
+
+void apply_control_winds(const monster* mon);
 #endif