getfaday - get abbreviated days of week names
Getfaday returns a pointer to an array of 7 character pointers.
Each of these pointers point to a null terminated string
corresponding to a 3 character abbreviation of the names of each
day in a week (Sunday through Saturday).
The abbreviated day names are retrieved from the country format
structure (see fcountry(C-3)).
C/Base Reference Manual Chapter 13, "Formatting Data Values"