Re: [PATCH for 4.6] configure: don't silently disable systemd support

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-09-09 at 23:35 +0100, Wei Liu wrote:
> Originally when user runs ./configure --enable-systemd and systemd
> development library is not available the build system silently disables
> systemd support. This is not in line with normal expectation.
> 
> Instead, configure should error out when user has asked for systemd
> support but development libraries can't be found.
> 
> Reported-by: George Dunlap <george.dunlap@eu.citrix.com>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> ---
> Please rerun ./autogen.sh.
> ---
>  m4/systemd.m4 | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/m4/systemd.m4 b/m4/systemd.m4
> index 8284993..84508a1 100644
> --- a/m4/systemd.m4
> +++ b/m4/systemd.m4
> @@ -85,7 +85,11 @@ AC_DEFUN([AX_CHECK_SYSTEMD], [
>  		AC_DEFINE([HAVE_SYSTEMD], [1], [Systemd available and
> enabled])
>  			systemd=y
>  			AX_CHECK_SYSTEMD_LIBS()
> -	    ],[systemd=n])
> +	    ],[
> +> 	> 	> AS_IF([test "x$enable_systemd" != "x"],

At this point the value of enable_systemd is either empty or ...what...? I
think "yes"?, with "no" having been ruled out earlier?

Or can it be just "y"?

I could live with this version, but I think it would be less of a brain ben
der if the check was inverted to be "x$enable_systemd" = "xyes" i.e. more
explicit.

Ian.