Package libnetfilter-conntrack depends on package libnfnetlink. iptables
checks package libnetfilter-conntrack whatever its package config
libnfnetlink is enabled or not. When libnfnetlink is disabled but
package libnetfilter-conntrack exists, it fails randomly with:

| In file included from .../iptables/1.4.21-r0/iptables-1.4.21/extensions/libxt_connlabel.c:8:0:
| .../tmp/sysroots/qemumips/usr/include/libnetfilter_conntrack/libnetfilter_conntrack.h:14:42: fatal error: libnfnetlink/linux_nfnetlink.h: No such file or directory
| compilation terminated.
| GNUmakefile:96: recipe for target 'libxt_connlabel.oo' failed

Only check libnetfilter-conntrack when libnfnetlink is enabled to fix it.

Upstream-Status: Pending

Signed-off-by: Kai Kang <kai.kang@windriver.com>

diff --git a/configure.ac b/configure.ac
index 5d7e62b..e331ee7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -88,8 +88,12 @@ if test "$ac_cv_header_linux_ip_vs_h" != "yes"; then
 	blacklist_modules="$blacklist_modules ipvs";
 fi;
 
-PKG_CHECK_MODULES([libnetfilter_conntrack], [libnetfilter_conntrack >= 1.0.4],
+nfconntrack=0
+AS_IF([test "x$enable_libnfnetlink" = "xyes"], [
+  PKG_CHECK_MODULES([libnetfilter_conntrack], [libnetfilter_conntrack >= 1.0.4],
 	[nfconntrack=1], [nfconntrack=0])
+  ])
+
 AM_CONDITIONAL([HAVE_LIBNETFILTER_CONNTRACK], [test "$nfconntrack" = 1])
 
 if test "$nfconntrack" -ne 1; then