Returns the name or version of the locale for the category specified by
mask.
The possible values for the mask are the same as those in
newlocale(3),
when requesting the locale name.
Specify the bitwise OR of
LC_VERSION_MASK
and another mask value to request a version string.
Version strings can be compared to detect changes to the locale's definition.
The structure of the version string is unspecified.
Currently, version information is only available for
LC_COLLATE_MASK,
and an empty string is returned for other categories.
If more than one bit in the mask is set, not counting
LC_VERSION_MASK,
the returned value is undefined.
