Subject: Re: [bug-diffutils] bug#24248: [patch] avoid duplicate definition of global variable presume_output_tty

From: Jim Meyering <[email-masked]>
Date: Tue, 16 Aug 2016 22:22:28 -0700

On Tue, Aug 16, 2016 at 10:09 PM, Jim Meyering <[email-masked]> wrote:
...
> I will look into adding -fno-common when it is accepted.

Here's the patch for that:
From 24792668f02cb915a170a8098d945da325287288 Mon Sep 17 00:00:00 2001
From: Jim Meyering <[email-masked]>
Date: Tue, 16 Aug 2016 22:20:28 -0700
Subject: [PATCH] build: arrange to build with -fno-common, when possible

* configure.ac (WERROR_CFLAGS): Add -fno-common, when possible.
This would have prevented the duplicate definition of
presume_output_tty that was fixed in v3.4-10-gc2dc91f.
---
 configure.ac | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure.ac b/configure.ac
index a473d66..936338f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -109,6 +109,7 @@ if test "$gl_gcc_warnings" = yes; then

   gl_WARN_ADD([-fdiagnostics-show-option])
   gl_WARN_ADD([-funit-at-a-time])
+  gl_WARN_ADD([-fno-common])

   AC_SUBST([WARN_CFLAGS])

-- 
2.8.0-rc2