--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/config/netbsd.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,54 @@
+/* Functions for generic NetBSD as target machine for GNU C compiler.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "varasm.h"
+#include "netbsd-protos.h"
+
+static void
+netbsd_patch_builtin (enum built_in_function fncode)
+{
+  tree fn = builtin_decl_explicit (fncode);
+  tree sym;
+  char *newname;
+
+  if (!fn)
+    return;
+
+  sym = DECL_ASSEMBLER_NAME (fn);
+  newname = ACONCAT (("__c99_", IDENTIFIER_POINTER (sym), NULL));
+
+  set_user_assembler_name (fn, newname);
+
+  fn = builtin_decl_implicit (fncode);
+  if (fn)
+    set_user_assembler_name (fn, newname);
+}
+
+void
+netbsd_patch_builtins (void)
+{
+  netbsd_patch_builtin (BUILT_IN_CABSF);
+  netbsd_patch_builtin (BUILT_IN_CABS);
+  netbsd_patch_builtin (BUILT_IN_CABSL);
+}