Problems building RTEMS for PowerPC

[dlb at cs.york.ac.uk (Darren Buttle)]

I have been trying to build a version of RTEMS to run on a PowerPC555
target.  During the build of gnat (from the bit_ada script), the
compilation fails with:

fatal error: run-time library configuration error cannot locate
"Zero_Cost_Exceptions" in file "system.ads" (entity not in package)
compilation abandoned 
make[1]: *** [ada.o] Error 1 make[1]: Leaving directory
`/home/dlb/rtems/tools/build-powerpc-tools/gcc/ada' 
make: *** [gnat1] Error 2 ERROR: 
**** FAILED **** gnat (gnat1)

While it is true that system.ads in the build tree doesn't contain
`Zero_Cost_Exceptions', I can't locate a reference to the entity
`Zero_Cost_Exceptions' anywhere in either the gcc of gnat source code.

Any suggestions of how I can resolve this problem?

Many thanks,

Darren Buttle