Phases of the moon

Just as in real life, the NetHack world goes through several phases of the moon. Probably unlike real life, these phases have a real effect on gameplay.

The moon phase is determined at the start of the game; if you save and restart the game will remain in the phase it was when you first started. The moon phases are determined by your system clock. Technically it is possible to change the clock to get a desired moon phase, but this is considered cheating.

During a full moon:
 * Your base luck is increased by one.
 * Werecreatures, especially at night, will usually be in their animal form.
 * Dogs will howl at night when #chatted to.
 * You have a chance of not being able to tame dogs at night.

During a new moon:
 * Contrary to popular belief, luck is not decreased.
 * If a cockatrice uses its hissing attack and you have no lizard corpse, you will always start turning into stone, rather than having a 1-in-10 chance.