Re: [PATCH for-4.5] systemd: use pkg-config to determine systemd library availability

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

On Wed, 2014-12-03 at 11:26 +0100, Olaf Hering wrote:
> On Tue, Dec 02, Konrad Rzeszutek Wilk wrote:
> 
> > On Tue, Dec 02, 2014 at 03:11:30PM +0000, Wei Liu wrote:
> > > AC_CHECK_LIB fails on Debian Jessie since the ld flag it generates is
> > > incorrect, even in the event systemd library is available.  Use
> > > PKG_CHECK_MODULES instead.
> > > 
> > > Tested on Debian Jessie and Arch Linux.
> > 
> > And Fedora and SuSE? CC-ing the other distro maintainers
> > for their input.
> 
> I'm fine with that. But:
> 
> It seems be that sd_listen_fds() is new in v209. It was backported to
> v208 in openSUSE 13.1. So there should be some detection if
> sd_listen_fds() is really available. Looks like this patch removes the
> check.

Ah I didn't know about the sd_listen_fds thing, so I think that what we
need then is to use pkg-config first to determine if systemd-daemon is
present at all, and then check for specific symbols we require using the
pkg-config supplied CFLAGS and LDFLAGS rather than assuming
-lsystemd-daemon.

Ian.

> 
> I get this from pkg-config:
> 
> root@optiplex:/work/olaf/13.1/github/olafhering/xen.git # pkg-config --cflags libsystemd-daemon ; echo $?
> 
> 0
> root@optiplex:/work/olaf/13.1/github/olafhering/xen.git # pkg-config --libs libsystemd-daemon ; echo $?
> -lsystemd-daemon 
> 0
> 
> Olaf