One more problem related with vcl/source/glyphs/gcach_ftyp.cxx. I noticed the
following piece of code:

        if( pHHEA != NULL )
        {
            // extleading formula from www.microsoft.com/typography/otspec/recom.htm
            int nExtLeading = pHHEA->Line_Gap;
            nExtLeading -= (pOS2->usWinAscent + pOS2->usWinDescent);
            nExtLeading -= (pHHEA->Ascender - pHHEA->Descender);
            if( nExtLeading > 0 )
                rTo.mnExtLeading = (long)(nExtLeading * fScale + 0.5);
        }

Frankly speaking, I don't understand how this code may correspond to the
referenced page of specification, which actually recommends the following
formula for calculating external leading:

MAX(0, LineGap - ((usWinAscent + usWinDescent) - (Ascender - Descender)))

As far as I can see, the problem lies in the extra pair of parentheseis: the
specification recommends to subtract the difference of (usWinAscent +
usWinAscent) and (Ascender - Descender) from LineGap, while in the current code
both these values are subtracted sequentially. Such method of calculation seems
to make no sense, as it will almost certainly result into a negative value, thus
making the whole piece of code unusable.