(CONSTRUCTOR_NAME_FORMAT): Let config.h override this.

From-SVN: r2817

gcc/tree.h

@@ -965,11 +965,13 @@ union tree_node
 #endif
 
 /* Format for global names of constructor and destructor functions.  */
+#ifndef CONSTRUCTOR_NAME_FORMAT  /* Some machines need to override this.  */
 #ifndef NO_DOLLAR_IN_LABEL
 #define CONSTRUCTOR_NAME_FORMAT "_GLOBAL_$I$%s"
 #else
 #define CONSTRUCTOR_NAME_FORMAT "_GLOBAL_.I.%s"
 #endif
+#endif
 
 /* The following functions accept a wide integer argument.  Rather than
    having to cast on every function call, we use a macro instead, that is