use compatible check for dot version

[Bill Spitzak]

I can't get either of those to work, but how about this:

  dot_version=`$DOT -V 2>&1 | $GREP -o '[0-9]*\.[0-9]*\.[0-9]*'`

That seems to produce "2.26.3" on my machine.

On 03/31/2015 09:17 AM, hector.oron at gmail.com wrote:
> From: Hector Oron <hector.oron at collabora.co.uk>
>
> Hello,
>
>    configure uses grep -oP to check for dot version in the following form:
>      dot_version=`$DOT -V 2>&1|$GREP -oP '(?<=version\W)@<:@0-9.@:>@*(?=\W(.*))'`
>    that is not supported in old grep versions.
>    The proposed patch uses equivalent sed form instead.
>      dot_version=`$DOT -V 2>&1|$SED -ne 's/.*version \([[0-9.]]*\) .*/\1/p'`
>
> Hector Oron (1):
>    configure.ac: use compatible check for dot version
>
>   configure.ac | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>