rs6000.h (SUBTARGET_OVERRIDE_OPTIONS): Define.

	* rs6000/rs6000.h (SUBTARGET_OVERRIDE_OPTIONS): Define.
	(OVERRIDE_OPTIONS): Call it.

From-SVN: r8965

gcc/config/rs6000/rs6000.h

@@ -268,7 +268,16 @@ extern char *rs6000_cpu_string;
 
    On the RS/6000 this is used to define the target cpu type.  */
 
-#define OVERRIDE_OPTIONS rs6000_override_options ()
+#define OVERRIDE_OPTIONS \
+do {				\
+  rs6000_override_options ();	\
+  SUBTARGET_OVERRIDE_OPTIONS;	\
+} while (0)
+
+/* For OS-dependent options */
+#ifndef SUBTARGET_OVERRIDE_OPTIONS
+#define SUBTARGET_OVERRIDE_OPTIONS
+#endif
 
 /* Show we can debug even without a frame pointer.  */
 #define CAN_DEBUG_WITHOUT_FP