fixinclude, math.h and Darwin???

[Jack Howarth]

   Can anyone explain exactly how and when the file...

gcc/fixincludes/tests/base/architecture/ppc/math.h

is used when building gcc on Darwin PPC? I ask because I
just noticed that it contains the remapping of the long
double math calls to use the appended $LDBL128 suffix.
I am wondering if it is possible that our problem with
these long double calls in gfortran on Darwin PPC could
be as simple as gfortran not using this fixed math header
on Darwin PPC. Thanks in advance for any clarifications.
              Jack