* The "size" parameter is the size of "out" not "in", and the
return size_t parameter is supposed to always have the total amount
of wchar_ts needed, not how many are actually used.
* In the case where "outSize == 0", we set "requiredSize" and then
return.
Fixes crashes seen in glib2 Unicode collation routines, which
are used in GTK file dialogs.
Thanks to PulkoMandy for glancing at this.
218604196a