Computes a list of applicable locale names, which can be used to e.g. construct locale-dependent filenames or search paths. The returned list is sorted from most desirable to least desirable and always contains the default locale “C”.
For example, if LANGUAGE=de:en_US, then the returned list is “de”, “en_US”, “en”, “C”.
This function consults the environment variables
LANG to find the list of locales specified by the user.