Hello,

The idea of doing this change has been kicking around for some time.

At present TARGET_LONG_DOUBLE_FORMAT defaults to floatformat_unknown 
when the target doesn't specify it.  This patch changes things so that 
it defaults to ieee_double and in doing so matches the default value of 
TARGET_LONG_DOUBLE_BIT.

Any target that didn't define it is going get this value defined. 
Playing around with the PPC (which doesn't define this).  I have a 
feeling this is a good move.

Before:

(top-gdb) print (long double)1
$2 = 0
(top-gdb) print (double)1
$3 = 1

after:

(gdb) print (long double)1
$1 = 1
(gdb) print (double)1
$2 = 1

thoughts.  Like IEEE_FLOAT this isn't ment to break things .....

Thoughts?  Probably commit it in about a week.

Andrew