Re: [Qemu-devel] [PATCH v2 1/1] configure: unset interfering variables

[Eric Blake]

On 05/28/2014 04:39 AM, Cornelia Huck wrote:
> The check for big or little endianness relies on grep reporting
> match/non-match on the generated binary. If the user specified
> --binary-files=without-match in their GREP_OPTIONS, this will fail.
> 
> Let's follow what autoconf does and unset GREP_OPTIONS and CLICOLOR_FORCE
> at the beginning of the script.
> 
> Reported-by: Eugene (jno) Dvurechenski <address@hidden>
> Suggested-by: Markus Armbruster <address@hidden>
> Signed-off-by: Cornelia Huck <address@hidden>
> ---
>  configure | 5 +++++
>  1 file changed, 5 insertions(+)

> 
> diff --git a/configure b/configure
> index 0e516f9..525da56 100755
> --- a/configure
> +++ b/configure
> @@ -3,6 +3,11 @@
>  # qemu configure script (c) 2003 Fabrice Bellard
>  #
>  
> +# Unset some variables known to interfere with behavior of common tools,
> +# just as autoconf does.
> +CLICOLOR_FORCE= GREP_OPTIONS=
> +unset CLICOLOR_FORCE GREP_OPTIONS

Autoconf does it in two steps to work around a bug in bash 2 where
unsetting a variable that is not set would crash bash.  But these days,
all shells on all systems where qemu is compiled don't have that bug.
You could drop the 'CLICOLOR_FORCE= GREP_OPTIONS=' line with no negative
effect, other than a future reader wondering why you differ from
autoconf.  So I don't care if you keep it in.

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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