Don't use printf %n.

Index: gcc/genmodes.c
--- gcc/genmodes.c.orig
+++ gcc/genmodes.c
@@ -786,7 +786,9 @@ calc_wider_mode (void)
 
 #define tagged_printf(FMT, ARG, TAG) do {		\
   int count_;						\
-  printf ("  " FMT ",%n", ARG, &count_);		\
+  count_ = printf ("  " FMT ",", ARG);			\
+  if (count_ < 0)					\
+    count_ = 0;						\
   printf ("%*s/* %s */\n", 27 - count_, "", TAG);	\
 } while (0)
 
@@ -821,7 +823,9 @@ enum machine_mode\n{");
     for (m = modes[c]; m; m = m->next)
       {
 	int count_;
-	printf ("  %smode,%n", m->name, &count_);
+	count_ = printf ("  %smode,", m->name);
+	if (count_ < 0)
+	  count_ = 0;
 	printf ("%*s/* %s:%d */\n", 27 - count_, "",
 		 trim_filename (m->file), m->line);
       }