Lfun:	set_extra_spell - control extra spell handling

Synopsis:
	void set_extra_spell(int spell_flag)

Description:
	The set_extra_spell call is used to handle extra_spell functionality.
	If spell_flag is 1, each combat round a function named extra_spell
	is called in the monster to make extra spells (or any other actions)
	possible.
	
	If spell flag is 0, those calls are disabled again.

Return value:
	none

Examples:
	set_extra_spell(1);

	extra_spell() {
		/* cast a spell here, for example using spell */
	}

See also: living/spell