[Devel] on ((s*)0)->f constructs

[Tom Kacvinsky]

I was taking alook in include/freetype/internal/ftstream.h,
and saw this:

#define FT_FIELD_SIZE( f ) \
          (FT_Byte)sizeof ( ((FT_STRUCTURE*)0)->f )

#define FT_FIELD_SIZE_DELTA( f ) \
          (FT_Byte)sizeof ( ((FT_STRUCTURE*)0)->f[0] )

Considering Rich Stephens' report about ((s*)0)->f constructs causing the AS400
compiler to barf, I tend to think that the above constructs also might cause
problems.  Unfortunately, I can't think of a way to get around use of ((s*)0)->f
in the above macros.