[libvirt] nwfilter: Don't compile nwfilter driver on other systems than Linux

[Stefan Berger]

  Don't compile the nwfilter driver (instantiating the rules) on other 
systems than Linux.

Signed-off-by: Stefan Berger <stefanb at us.ibm.com>

diff --git a/configure.ac b/configure.ac
index 23181dd..4cb0f50 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1361,7 +1361,7 @@ fi
  AM_CONDITIONAL([WITH_SECRETS], [test "$with_secrets" = "yes"])

  with_nwfilter=yes
-if test "$with_libvirtd" = "no"; then
+if test "$with_libvirtd" = "no" || test `uname -s` != "Linux"; then
    with_nwfilter=no
  fi
  if test "$with_nwfilter" = "yes" ; then