Index: configure.ac
===================================================================
--- configure.ac	(revision 17653)
+++ configure.ac	(working copy)
@@ -316,6 +316,9 @@
 
 AC_SUBST(OPENSSL_LIBS)
 
+# Since upgrading to 1.1.1, libpcap seems to require libnl, at least on x86_64.
+AC_SEARCH_LIBS(nlmsg_free, nl)
+
 dnl Check whether libpcap is already available
 have_libpcap=no
 
Index: configure
===================================================================
--- configure	(revision 17653)
+++ configure	(working copy)
@@ -6731,6 +6731,95 @@
 
 
 
+# Since upgrading to 1.1.1, libpcap seems to require libnl, at least on x86_64.
+{ $as_echo "$as_me:$LINENO: checking for library containing nlmsg_free" >&5
+$as_echo_n "checking for library containing nlmsg_free... " >&6; }
+if test "${ac_cv_search_nlmsg_free+set}" = set; then
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char nlmsg_free ();
+int
+main ()
+{
+return nlmsg_free ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' nl; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext && {
+	 test "$cross_compiling" = yes ||
+	 $as_test_x conftest$ac_exeext
+       }; then
+  ac_cv_search_nlmsg_free=$ac_res
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+fi
+
+rm -rf conftest.dSYM
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext
+  if test "${ac_cv_search_nlmsg_free+set}" = set; then
+  break
+fi
+done
+if test "${ac_cv_search_nlmsg_free+set}" = set; then
+  :
+else
+  ac_cv_search_nlmsg_free=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:$LINENO: result: $ac_cv_search_nlmsg_free" >&5
+$as_echo "$ac_cv_search_nlmsg_free" >&6; }
+ac_res=$ac_cv_search_nlmsg_free
+if test "$ac_res" != no; then
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
+
 have_libpcap=no
 
 # By default, search for pcap library