Return the set of IPA characters that are defined in normal form C in the
	spec. As of 2015, this is only the voiceless palatal fricative, ç.

def get_precomposed_chars():
	"""
	Return the set of IPA characters that are defined in normal form C in the
	spec. As of 2015, this is only the voiceless palatal fricative, ç.
	"""
	return set([
		letter for letter in chart.consonants
		if unicodedata.normalize('NFD', letter) != letter ])