tighten the toplevel guard on ibm-ldouble.c

2018-10-12  Olivier Hainque  <hainque@adacore.com>

        * config/rs6000/ibm-ldouble.c: Augment the toplevel guard with
        defined (__FLOAT128_TYPE__) || defined (__LONG_DOUBLE_128__).

From-SVN: r265135

libgcc/ChangeLog

+2018-10-12  Olivier Hainque  <hainque@adacore.com>
+
+	* config/rs6000/ibm-ldouble.c: Augment the toplevel guard with
+	defined (__FLOAT128_TYPE__) || defined (__LONG_DOUBLE_128__).
+
 2018-10-08  Paul Koning  <ni1d@arrl.net>
 
 	* config/pdp11/t-pdp11: Remove -mfloat32 switch.

libgcc/config/rs6000/ibm-ldouble.c

@@ -46,7 +46,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    the lower numbered register or lower addressed memory.  */
 
 #if (defined (__MACH__) || defined (__powerpc__) || defined (_AIX)) \
-    && !defined (__rtems__)
+  && !defined (__rtems__) \
+  && (defined (__LONG_DOUBLE_128__) || defined (__FLOAT128_TYPE__))
 
 #define fabs(x) __builtin_fabs(x)
 #define isless(x, y) __builtin_isless (x, y)