[Lazarus] Fit TFrom's width so that it's caption isn't cut off?

[Bart]

Hi all,

Is there a crossplatform way to determine the necessary width for a
TForm so that it's caption wont be cut off?
It does have to work regardless of the (amount of) bordericons the form has.

NB. Needed for http://bugs.freepascal.org/view.php?id=19637

Bart