From 37f4615e91bedc139f60cb2bb771327a39ed9d8d Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@ovn.org>
Date: Mon, 5 Dec 2016 14:29:35 -0800
Subject: [PATCH] acinclude: Fix -Wstrict-prototypes and -Wold-style-definition
 detection.

AC_LANG_PROGRAM(,) uses a program like this:

    int main() { return 0; }

but that triggers warnings for -Wstrict-prototypes and for
-Wold-style-definition, since this definition of main() lacks a prototype
and is therefore old-style.  This meant that -Wstrict-prototypes and
-Wold-style-definition weren't being turned on for new-enough GCC.  This
commit fixes the problem by changing the program that is test-compiled to:

    int x;

which doesn't make any compilers mad, as far as I know.

I recently upgraded to GCC 6.1 and just now noticed the issue, so I think
that GCC somewhere between version 4.9 and version 6.1 must have started
warning about main() when it's declared this way.

Also, fix a few functions that lacked prototypes.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Andy Zhou <azhou@ovn.org>
---
 acinclude.m4       | 12 ++++++++++--
 lib/perf-counter.c |  6 +++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index 866e4373b..8b9297ae7 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1,6 +1,6 @@
 # -*- autoconf -*-
 
-# Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
+# Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Nicira, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -784,7 +784,15 @@ AC_DEFUN([_OVS_CHECK_CC_OPTION], [dnl
      dnl    0
      dnl    %
      CFLAGS="$CFLAGS $WERROR $1"
-     AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,)], [if test -s conftest.err && grep "unrecognized option" conftest.err; then ovs_cv_name[]=no; else ovs_cv_name[]=yes; fi], [ovs_cv_name[]=no])
+     AC_COMPILE_IFELSE(
+       [AC_LANG_SOURCE([int x;])],
+       [if test -s conftest.err && grep "unrecognized option" conftest.err
+        then
+          ovs_cv_name[]=no
+        else
+          ovs_cv_name[]=yes
+        fi],
+       [ovs_cv_name[]=no])
      CFLAGS="$ovs_save_CFLAGS"])
   if test $ovs_cv_name = yes; then
     m4_if([$2], [], [:], [$2])
diff --git a/lib/perf-counter.c b/lib/perf-counter.c
index da60df7e7..c4458d2f5 100644
--- a/lib/perf-counter.c
+++ b/lib/perf-counter.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015 Nicira, Inc.
+ * Copyright (c) 2015, 2016 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -146,7 +146,7 @@ perf_counters_to_ds(struct ds *ds)
  * Caller is responsible for free memory.
  */
 char *
-perf_counters_to_string()
+perf_counters_to_string(void)
 {
     struct ds ds;
 
@@ -176,7 +176,7 @@ perf_counters_clear(void)
 }
 
 void
-perf_counters_destroy()
+perf_counters_destroy(void)
 {
     struct shash_node *node, *next;
 
-- 
2.39.2