[3.3 branch] Ada bootstrap failure on powerpc-linux

[David Edelsohn]

>>>>> Matthias Klose writes:

Matthias> ../targtyps.o(.text+0x6a): In function `get_target_long_double_size':
Matthias> : undefined reference to `rs6000_long_double_type_size'
Matthias> ../targtyps.o(.text+0x6e): In function `get_target_long_double_size':
Matthias> : undefined reference to `rs6000_long_double_type_size'

	This has been discussed on the GCC mailinglist before.  Because
Gnat cannot link with the GCC infrastructure defining this variable to
provide variable size, it needs to assume 64-bit long double for now.

David