[Freetype] tmAscent in Windows fontMetrics

[Roman Bednarek]

Hi.
  In Windows version of my appplication I am using the following value
textmetric.tmAscent+textmetric.tmInternalLeading+textmetric.tmExternalLeading.
I have to be compatible in freetype version, but I cannot get the same
value from FT_Face fields. I am adding an arbitrary(guess) value to
face->ascender which is not really good solution.
  Is there a good way to get exactly the same value using freetype?

   Roman Bednarek